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2021-11-19libbpf: Change bpf_program__set_extra_flags to bpf_program__set_flagsFlorent Revest
bpf_program__set_extra_flags has just been introduced so we can still change it without breaking users. This new interface is a bit more flexible (for example if someone wants to clear a flag). Signed-off-by: Florent Revest <revest@chromium.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211119180035.1396139-1-revest@chromium.org
2021-11-19libbpf: Add runtime APIs to query libbpf versionAndrii Nakryiko
Libbpf provided LIBBPF_MAJOR_VERSION and LIBBPF_MINOR_VERSION macros to check libbpf version at compilation time. This doesn't cover all the needs, though, because version of libbpf that application is compiled against doesn't necessarily match the version of libbpf at runtime, especially if libbpf is used as a shared library. Add libbpf_major_version() and libbpf_minor_version() returning major and minor versions, respectively, as integers. Also add a convenience libbpf_version_string() for various tooling using libbpf to print out libbpf version in a human-readable form. Currently it will return "v0.6", but in the future it can contains some extra information, so the format itself is not part of a stable API and shouldn't be relied upon. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20211118174054.2699477-1-andrii@kernel.org
2021-11-11libbpf: Support BTF_KIND_TYPE_TAGYonghong Song
Add libbpf support for BTF_KIND_TYPE_TAG. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211112012614.1505315-1-yhs@fb.com
2021-11-11libbpf: Make perf_buffer__new() use OPTS-based interfaceAndrii Nakryiko
Add new variants of perf_buffer__new() and perf_buffer__new_raw() that use OPTS-based options for future extensibility ([0]). Given all the currently used API names are best fits, re-use them and use ___libbpf_override() approach and symbol versioning to preserve ABI and source code compatibility. struct perf_buffer_opts and struct perf_buffer_raw_opts are kept as well, but they are restructured such that they are OPTS-based when used with new APIs. For struct perf_buffer_raw_opts we keep few fields intact, so we have to also preserve the memory location of them both when used as OPTS and for legacy API variants. This is achieved with anonymous padding for OPTS "incarnation" of the struct. These pads can be eventually used for new options. [0] Closes: https://github.com/libbpf/libbpf/issues/311 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211111053624.190580-6-andrii@kernel.org
2021-11-11libbpf: Ensure btf_dump__new() and btf_dump_opts are future-proofAndrii Nakryiko
Change btf_dump__new() and corresponding struct btf_dump_ops structure to be extensible by using OPTS "framework" ([0]). Given we don't change the names, we use a similar approach as with bpf_prog_load(), but this time we ended up with two APIs with the same name and same number of arguments, so overloading based on number of arguments with ___libbpf_override() doesn't work. Instead, use "overloading" based on types. In this particular case, print callback has to be specified, so we detect which argument is a callback. If it's 4th (last) argument, old implementation of API is used by user code. If not, it must be 2nd, and thus new implementation is selected. The rest is handled by the same symbol versioning approach. btf_ext argument is dropped as it was never used and isn't necessary either. If in the future we'll need btf_ext, that will be added into OPTS-based struct btf_dump_opts. struct btf_dump_opts is reused for both old API and new APIs. ctx field is marked deprecated in v0.7+ and it's put at the same memory location as OPTS's sz field. Any user of new-style btf_dump__new() will have to set sz field and doesn't/shouldn't use ctx, as ctx is now passed along the callback as mandatory input argument, following the other APIs in libbpf that accept callbacks consistently. Again, this is quite ugly in implementation, but is done in the name of backwards compatibility and uniform and extensible future APIs (at the same time, sigh). And it will be gone in libbpf 1.0. [0] Closes: https://github.com/libbpf/libbpf/issues/283 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211111053624.190580-5-andrii@kernel.org
2021-11-11libbpf: Turn btf_dedup_opts into OPTS-based structAndrii Nakryiko
btf__dedup() and struct btf_dedup_opts were added before we figured out OPTS mechanism. As such, btf_dedup_opts is non-extensible without breaking an ABI and potentially crashing user application. Unfortunately, btf__dedup() and btf_dedup_opts are short and succinct names that would be great to preserve and use going forward. So we use ___libbpf_override() macro approach, used previously for bpf_prog_load() API, to define a new btf__dedup() variant that accepts only struct btf * and struct btf_dedup_opts * arguments, and rename the old btf__dedup() implementation into btf__dedup_deprecated(). This keeps both source and binary compatibility with old and new applications. The biggest problem was struct btf_dedup_opts, which wasn't OPTS-based, and as such doesn't have `size_t sz;` as a first field. But btf__dedup() is a pretty rarely used API and I believe that the only currently known users (besides selftests) are libbpf's own bpf_linker and pahole. Neither use case actually uses options and just passes NULL. So instead of doing extra hacks, just rewrite struct btf_dedup_opts into OPTS-based one, move btf_ext argument into those opts (only bpf_linker needs to dedup btf_ext, so it's not a typical thing to specify), and drop never used `dont_resolve_fwds` option (it was never used anywhere, AFAIK, it makes BTF dedup much less useful and efficient). Just in case, for old implementation, btf__dedup_deprecated(), detect non-NULL options and error out with helpful message, to help users migrate, if there are any user playing with btf__dedup(). The last remaining piece is dedup_table_size, which is another anachronism from very early days of BTF dedup. Since then it has been reduced to the only valid value, 1, to request forced hash collisions. This is only used during testing. So instead introduce a bool flag to force collisions explicitly. This patch also adapts selftests to new btf__dedup() and btf_dedup_opts use to avoid selftests breakage. [0] Closes: https://github.com/libbpf/libbpf/issues/281 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211111053624.190580-4-andrii@kernel.org
2021-11-11libbpf: Add ability to get/set per-program load flagsAndrii Nakryiko
Add bpf_program__flags() API to retrieve prog_flags that will be (or were) supplied to BPF_PROG_LOAD command. Also add bpf_program__set_extra_flags() API to allow to set *extra* flags, in addition to those determined by program's SEC() definition. Such flags are logically OR'ed with libbpf-derived flags. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211111051758.92283-2-andrii@kernel.org
2021-11-07libbpf: Unify low-level BPF_PROG_LOAD APIs into bpf_prog_load()Andrii Nakryiko
Add a new unified OPTS-based low-level API for program loading, bpf_prog_load() ([0]). bpf_prog_load() accepts few "mandatory" parameters as input arguments (program type, name, license, instructions) and all the other optional (as in not required to specify for all types of BPF programs) fields into struct bpf_prog_load_opts. This makes all the other non-extensible APIs variant for BPF_PROG_LOAD obsolete and they are slated for deprecation in libbpf v0.7: - bpf_load_program(); - bpf_load_program_xattr(); - bpf_verify_program(). Implementation-wise, internal helper libbpf__bpf_prog_load is refactored to become a public bpf_prog_load() API. struct bpf_prog_load_params used internally is replaced by public struct bpf_prog_load_opts. Unfortunately, while conceptually all this is pretty straightforward, the biggest complication comes from the already existing bpf_prog_load() *high-level* API, which has nothing to do with BPF_PROG_LOAD command. We try really hard to have a new API named bpf_prog_load(), though, because it maps naturally to BPF_PROG_LOAD command. For that, we rename old bpf_prog_load() into bpf_prog_load_deprecated() and mark it as COMPAT_VERSION() for shared library users compiled against old version of libbpf. Statically linked users and shared lib users compiled against new version of libbpf headers will get "rerouted" to bpf_prog_deprecated() through a macro helper that decides whether to use new or old bpf_prog_load() based on number of input arguments (see ___libbpf_overload in libbpf_common.h). To test that existing bpf_prog_load()-using code compiles and works as expected, I've compiled and ran selftests as is. I had to remove (locally) selftest/bpf/Makefile -Dbpf_prog_load=bpf_prog_test_load hack because it was conflicting with the macro-based overload approach. I don't expect anyone else to do something like this in practice, though. This is testing-specific way to replace bpf_prog_load() calls with special testing variant of it, which adds extra prog_flags value. After testing I kept this selftests hack, but ensured that we use a new bpf_prog_load_deprecated name for this. This patch also marks bpf_prog_load() and bpf_prog_load_xattr() as deprecated. bpf_object interface has to be used for working with struct bpf_program. Libbpf doesn't support loading just a bpf_program. The silver lining is that when we get to libbpf 1.0 all these complication will be gone and we'll have one clean bpf_prog_load() low-level API with no backwards compatibility hackery surrounding it. [0] Closes: https://github.com/libbpf/libbpf/issues/284 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211103220845.2676888-4-andrii@kernel.org
2021-10-28libbpf: Add "map_extra" as a per-map-type extra flagJoanne Koong
This patch adds the libbpf infrastructure for supporting a per-map-type "map_extra" field, whose definition will be idiosyncratic depending on map type. For example, for the bloom filter map, the lower 4 bits of map_extra is used to denote the number of hash functions. Please note that until libbpf 1.0 is here, the "bpf_create_map_params" struct is used as a temporary means for propagating the map_extra field to the kernel. Signed-off-by: Joanne Koong <joannekoong@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211027234504.30744-3-joannekoong@fb.com
2021-10-25libbpf: Add ability to fetch bpf_program's underlying instructionsAndrii Nakryiko
Add APIs providing read-only access to bpf_program BPF instructions ([0]). This is useful for diagnostics purposes, but it also allows a cleaner support for cloning BPF programs after libbpf did all the FD resolution and CO-RE relocations, subprog instructions appending, etc. Currently, cloning BPF program is possible only through hijacking a half-broken bpf_program__set_prep() API, which doesn't really work well for anything but most primitive programs. For instance, set_prep() API doesn't allow adjusting BPF program load parameters which are necessary for loading fentry/fexit BPF programs (the case where BPF program cloning is a necessity if doing some sort of mass-attachment functionality). Given bpf_program__set_prep() API is set to be deprecated, having a cleaner alternative is a must. libbpf internally already keeps track of linear array of struct bpf_insn, so it's not hard to expose it. The only gotcha is that libbpf previously freed instructions array during bpf_object load time, which would make this API much less useful overall, because in between bpf_object__open() and bpf_object__load() a lot of changes to instructions are done by libbpf. So this patch makes libbpf hold onto prog->insns array even after BPF program loading. I think this is a small price for added functionality and improved introspection of BPF program code. See retsnoop PR ([1]) for how it can be used in practice and code savings compared to relying on bpf_program__set_prep(). [0] Closes: https://github.com/libbpf/libbpf/issues/298 [1] https://github.com/anakryiko/retsnoop/pull/1 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211025224531.1088894-3-andrii@kernel.org
2021-10-22libbpf: Add btf__type_cnt() and btf__raw_data() APIsHengqi Chen
Add btf__type_cnt() and btf__raw_data() APIs and deprecate btf__get_nr_type() and btf__get_raw_data() since the old APIs don't follow the libbpf naming convention for getters which omit 'get' in the name (see [0]). btf__raw_data() is just an alias to the existing btf__get_raw_data(). btf__type_cnt() now returns the number of all types of the BTF object including 'void'. [0] Closes: https://github.com/libbpf/libbpf/issues/279 Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211022130623.1548429-2-hengqi.chen@gmail.com
2021-10-18bpf: Rename BTF_KIND_TAG to BTF_KIND_DECL_TAGYonghong Song
Patch set [1] introduced BTF_KIND_TAG to allow tagging declarations for struct/union, struct/union field, var, func and func arguments and these tags will be encoded into dwarf. They are also encoded to btf by llvm for the bpf target. After BTF_KIND_TAG is introduced, we intended to use it for kernel __user attributes. But kernel __user is actually a type attribute. Upstream and internal discussion showed it is not a good idea to mix declaration attribute and type attribute. So we proposed to introduce btf_type_tag as a type attribute and existing btf_tag renamed to btf_decl_tag ([2]). This patch renamed BTF_KIND_TAG to BTF_KIND_DECL_TAG and some other declarations with *_tag to *_decl_tag to make it clear the tag is for declaration. In the future, BTF_KIND_TYPE_TAG might be introduced per [3]. [1] https://lore.kernel.org/bpf/20210914223004.244411-1-yhs@fb.com/ [2] https://reviews.llvm.org/D111588 [3] https://reviews.llvm.org/D111199 Fixes: b5ea834dde6b ("bpf: Support for new btf kind BTF_KIND_TAG") Fixes: 5b84bd10363e ("libbpf: Add support for BTF_KIND_TAG") Fixes: 5c07f2fec003 ("bpftool: Add support for BTF_KIND_TAG") Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20211012164838.3345699-1-yhs@fb.com
2021-10-06libbpf: Deprecate bpf_{map,program}__{prev,next} APIs since v0.7Hengqi Chen
Deprecate bpf_{map,program}__{prev,next} APIs. Replace them with a new set of APIs named bpf_object__{prev,next}_{program,map} which follow the libbpf API naming convention ([0]). No functionality changes. [0] Closes: https://github.com/libbpf/libbpf/issues/296 Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20211003165844.4054931-2-hengqi.chen@gmail.com
2021-10-06libbpf: Add API that copies all BTF types from one BTF object to anotherAndrii Nakryiko
Add a bulk copying api, btf__add_btf(), that speeds up and simplifies appending entire contents of one BTF object to another one, taking care of copying BTF type data, adjusting resulting BTF type IDs according to their new locations in the destination BTF object, as well as copying and deduplicating all the referenced strings and updating all the string offsets in new BTF types as appropriate. This API is intended to be used from tools that are generating and otherwise manipulating BTFs generically, such as pahole. In pahole's case, this API is useful for speeding up parallelized BTF encoding, as it allows pahole to offload all the intricacies of BTF type copying to libbpf and handle the parallelization aspects of the process. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Link: https://lore.kernel.org/bpf/20211006051107.17921-2-andrii@kernel.org
2021-09-14libbpf: Add support for BTF_KIND_TAGYonghong Song
Add BTF_KIND_TAG support for parsing and dedup. Also added sanitization for BTF_KIND_TAG. If BTF_KIND_TAG is not supported in the kernel, sanitize it to INTs. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210914223025.246687-1-yhs@fb.com
2021-09-13libbpf: Make libbpf_version.h non-auto-generatedAndrii Nakryiko
Turn previously auto-generated libbpf_version.h header into a normal header file. This prevents various tricky Makefile integration issues, simplifies the overall build process, but also allows to further extend it with some more versioning-related APIs in the future. To prevent accidental out-of-sync versions as defined by libbpf.map and libbpf_version.h, Makefile checks their consistency at build time. Simultaneously with this change bump libbpf.map to v0.6. Also undo adding libbpf's output directory into include path for kernel/bpf/preload, bpftool, and resolve_btfids, which is not necessary because libbpf_version.h is just a normal header like any other. Fixes: 0b46b7550560 ("libbpf: Add LIBBPF_DEPRECATED_SINCE macro for scheduling API deprecations") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210913222309.3220849-1-andrii@kernel.org
2021-08-17libbpf: Add bpf_cookie to perf_event, kprobe, uprobe, and tp attach APIsAndrii Nakryiko
Wire through bpf_cookie for all attach APIs that use perf_event_open under the hood: - for kprobes, extend existing bpf_kprobe_opts with bpf_cookie field; - for perf_event, uprobe, and tracepoint APIs, add their _opts variants and pass bpf_cookie through opts. For kernel that don't support BPF_LINK_CREATE for perf_events, and thus bpf_cookie is not supported either, return error and log warning for user. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20210815070609.987780-12-andrii@kernel.org
2021-07-30libbpf: Add btf__load_vmlinux_btf/btf__load_module_btfHengqi Chen
Add two new APIs: btf__load_vmlinux_btf and btf__load_module_btf. btf__load_vmlinux_btf is just an alias to the existing API named libbpf_find_kernel_btf, rename to be more precisely and consistent with existing BTF APIs. btf__load_module_btf can be used to load module BTF, add it for completeness. These two APIs are useful for implementing tracing tools and introspection tools. This is part of the effort towards libbpf 1.0 ([0]). [0] Closes: https://github.com/libbpf/libbpf/issues/280 Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210730114012.494408-1-hengqi.chen@gmail.com
2021-07-29libbpf: Add split BTF support for btf__load_from_kernel_by_id()Quentin Monnet
Add a new API function btf__load_from_kernel_by_id_split(), which takes a pointer to a base BTF object in order to support split BTF objects when retrieving BTF information from the kernel. Reference: https://github.com/libbpf/libbpf/issues/314 Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20210729162028.29512-8-quentin@isovalent.com
2021-07-29libbpf: Rename btf__get_from_id() as btf__load_from_kernel_by_id()Quentin Monnet
Rename function btf__get_from_id() as btf__load_from_kernel_by_id() to better indicate what the function does. Change the new function so that, instead of requiring a pointer to the pointer to update and returning with an error code, it takes a single argument (the id of the BTF object) and returns the corresponding pointer. This is more in line with the existing constructors. The other tools calling the (soon-to-be) deprecated btf__get_from_id() function will be updated in a future commit. References: - https://github.com/libbpf/libbpf/issues/278 - https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0#btfh-apis Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20210729162028.29512-4-quentin@isovalent.com
2021-07-29libbpf: Rename btf__load() as btf__load_into_kernel()Quentin Monnet
As part of the effort to move towards a v1.0 for libbpf, rename btf__load() function, used to "upload" BTF information into the kernel, as btf__load_into_kernel(). This new name better reflects what the function does. References: - https://github.com/libbpf/libbpf/issues/278 - https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0#btfh-apis Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20210729162028.29512-3-quentin@isovalent.com
2021-07-23libbpf: Add bpf_map__pin_path functionEvgeniy Litvinenko
Add bpf_map__pin_path, so that the inconsistently named bpf_map__get_pin_path can be deprecated later. This is part of the effort towards libbpf v1.0: https://github.com/libbpf/libbpf/issues/307 Also, add a selftest for the new function. Signed-off-by: Evgeniy Litvinenko <evgeniyl@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210723221511.803683-1-evgeniyl@fb.com
2021-07-22libbpf: Export bpf_program__attach_kprobe_opts functionJiri Olsa
Export bpf_program__attach_kprobe_opts as a public API. Rename bpf_program_attach_kprobe_opts to bpf_kprobe_opts and turn it into OPTS struct. Suggested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Tested-by: Alan Maguire <alan.maguire@oracle.com> Link: https://lore.kernel.org/bpf/20210721215810.889975-4-jolsa@kernel.org
2021-07-16libbpf: BTF dumper support for typed dataAlan Maguire
Add a BTF dumper for typed data, so that the user can dump a typed version of the data provided. The API is int btf_dump__dump_type_data(struct btf_dump *d, __u32 id, void *data, size_t data_sz, const struct btf_dump_type_data_opts *opts); ...where the id is the BTF id of the data pointed to by the "void *" argument; for example the BTF id of "struct sk_buff" for a "struct skb *" data pointer. Options supported are - a starting indent level (indent_lvl) - a user-specified indent string which will be printed once per indent level; if NULL, tab is chosen but any string <= 32 chars can be provided. - a set of boolean options to control dump display, similar to those used for BPF helper bpf_snprintf_btf(). Options are - compact : omit newlines and other indentation - skip_names: omit member names - emit_zeroes: show zero-value members Default output format is identical to that dumped by bpf_snprintf_btf(), for example a "struct sk_buff" representation would look like this: struct sk_buff){ (union){ (struct){ .next = (struct sk_buff *)0xffffffffffffffff, .prev = (struct sk_buff *)0xffffffffffffffff, (union){ .dev = (struct net_device *)0xffffffffffffffff, .dev_scratch = (long unsigned int)18446744073709551615, }, }, ... If the data structure is larger than the *data_sz* number of bytes that are available in *data*, as much of the data as possible will be dumped and -E2BIG will be returned. This is useful as tracers will sometimes not be able to capture all of the data associated with a type; for example a "struct task_struct" is ~16k. Being able to specify that only a subset is available is important for such cases. On success, the amount of data dumped is returned. Signed-off-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/1626362126-27775-2-git-send-email-alan.maguire@oracle.com
2021-06-03libbpf: Move few APIs from 0.4 to 0.5 versionAndrii Nakryiko
Official libbpf 0.4 release doesn't include three APIs that were tentatively put into 0.4 section. Fix libbpf.map and move these three APIs: - bpf_map__initial_value; - bpf_map_lookup_and_delete_elem_flags; - bpf_object__gen_loader. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20210603004026.2698513-2-andrii@kernel.org
2021-05-25libbpf: Add libbpf_set_strict_mode() API to turn on libbpf 1.0 behaviorsAndrii Nakryiko
Add libbpf_set_strict_mode() API that allows application to simulate libbpf 1.0 breaking changes before libbpf 1.0 is released. This will help users migrate gradually and with confidence. For now only ALL or NONE options are available, subsequent patches will add more flags. This patch is preliminary for selftests/bpf changes. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20210525035935.1461796-2-andrii@kernel.org
2021-05-24bpf: Extend libbpf with bpf_map_lookup_and_delete_elem_flagsDenis Salopek
Add bpf_map_lookup_and_delete_elem_flags() libbpf API in order to use the BPF_F_LOCK flag with the map_lookup_and_delete_elem() function. Signed-off-by: Denis Salopek <denis.salopek@sartura.hr> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/15b05dafe46c7e0750d110f233977372029d1f62.1620763117.git.denis.salopek@sartura.hr
2021-05-19libbpf: Introduce bpf_map__initial_value().Alexei Starovoitov
Introduce bpf_map__initial_value() to read initial contents of mmaped data/rodata/bss maps. Note that bpf_map__set_initial_value() doesn't allow modifying kconfig map while bpf_map__initial_value() allows reading its values. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210514003623.28033-17-alexei.starovoitov@gmail.com
2021-05-19libbpf: Generate loader program out of BPF ELF file.Alexei Starovoitov
The BPF program loading process performed by libbpf is quite complex and consists of the following steps: "open" phase: - parse elf file and remember relocations, sections - collect externs and ksyms including their btf_ids in prog's BTF - patch BTF datasec (since llvm couldn't do it) - init maps (old style map_def, BTF based, global data map, kconfig map) - collect relocations against progs and maps "load" phase: - probe kernel features - load vmlinux BTF - resolve externs (kconfig and ksym) - load program BTF - init struct_ops - create maps - apply CO-RE relocations - patch ld_imm64 insns with src_reg=PSEUDO_MAP, PSEUDO_MAP_VALUE, PSEUDO_BTF_ID - reposition subprograms and adjust call insns - sanitize and load progs During this process libbpf does sys_bpf() calls to load BTF, create maps, populate maps and finally load programs. Instead of actually doing the syscalls generate a trace of what libbpf would have done and represent it as the "loader program". The "loader program" consists of single map with: - union bpf_attr(s) - BTF bytes - map value bytes - insns bytes and single bpf program that passes bpf_attr(s) and data into bpf_sys_bpf() helper. Executing such "loader program" via bpf_prog_test_run() command will replay the sequence of syscalls that libbpf would have done which will result the same maps created and programs loaded as specified in the elf file. The "loader program" removes libelf and majority of libbpf dependency from program loading process. kconfig, typeless ksym, struct_ops and CO-RE are not supported yet. The order of relocate_data and relocate_calls had to change, so that bpf_gen__prog_load() can see all relocations for a given program with correct insn_idx-es. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210514003623.28033-15-alexei.starovoitov@gmail.com
2021-05-17libbpf: Add low level TC-BPF management APIKumar Kartikeya Dwivedi
This adds functions that wrap the netlink API used for adding, manipulating, and removing traffic control filters. The API summary: A bpf_tc_hook represents a location where a TC-BPF filter can be attached. This means that creating a hook leads to creation of the backing qdisc, while destruction either removes all filters attached to a hook, or destroys qdisc if requested explicitly (as discussed below). The TC-BPF API functions operate on this bpf_tc_hook to attach, replace, query, and detach tc filters. All functions return 0 on success, and a negative error code on failure. bpf_tc_hook_create - Create a hook Parameters: @hook - Cannot be NULL, ifindex > 0, attach_point must be set to proper enum constant. Note that parent must be unset when attach_point is one of BPF_TC_INGRESS or BPF_TC_EGRESS. Note that as an exception BPF_TC_INGRESS|BPF_TC_EGRESS is also a valid value for attach_point. Returns -EOPNOTSUPP when hook has attach_point as BPF_TC_CUSTOM. bpf_tc_hook_destroy - Destroy a hook Parameters: @hook - Cannot be NULL. The behaviour depends on value of attach_point. If BPF_TC_INGRESS, all filters attached to the ingress hook will be detached. If BPF_TC_EGRESS, all filters attached to the egress hook will be detached. If BPF_TC_INGRESS|BPF_TC_EGRESS, the clsact qdisc will be deleted, also detaching all filters. As before, parent must be unset for these attach_points, and set for BPF_TC_CUSTOM. It is advised that if the qdisc is operated on by many programs, then the program at least check that there are no other existing filters before deleting the clsact qdisc. An example is shown below: DECLARE_LIBBPF_OPTS(bpf_tc_hook, .ifindex = if_nametoindex("lo"), .attach_point = BPF_TC_INGRESS); /* set opts as NULL, as we're not really interested in * getting any info for a particular filter, but just * detecting its presence. */ r = bpf_tc_query(&hook, NULL); if (r == -ENOENT) { /* no filters */ hook.attach_point = BPF_TC_INGRESS|BPF_TC_EGREESS; return bpf_tc_hook_destroy(&hook); } else { /* failed or r == 0, the latter means filters do exist */ return r; } Note that there is a small race between checking for no filters and deleting the qdisc. This is currently unavoidable. Returns -EOPNOTSUPP when hook has attach_point as BPF_TC_CUSTOM. bpf_tc_attach - Attach a filter to a hook Parameters: @hook - Cannot be NULL. Represents the hook the filter will be attached to. Requirements for ifindex and attach_point are same as described in bpf_tc_hook_create, but BPF_TC_CUSTOM is also supported. In that case, parent must be set to the handle where the filter will be attached (using BPF_TC_PARENT). E.g. to set parent to 1:16 like in tc command line, the equivalent would be BPF_TC_PARENT(1, 16). @opts - Cannot be NULL. The following opts are optional: * handle - The handle of the filter * priority - The priority of the filter Must be >= 0 and <= UINT16_MAX Note that when left unset, they will be auto-allocated by the kernel. The following opts must be set: * prog_fd - The fd of the loaded SCHED_CLS prog The following opts must be unset: * prog_id - The ID of the BPF prog The following opts are optional: * flags - Currently only BPF_TC_F_REPLACE is allowed. It allows replacing an existing filter instead of failing with -EEXIST. The following opts will be filled by bpf_tc_attach on a successful attach operation if they are unset: * handle - The handle of the attached filter * priority - The priority of the attached filter * prog_id - The ID of the attached SCHED_CLS prog This way, the user can know what the auto allocated values for optional opts like handle and priority are for the newly attached filter, if they were unset. Note that some other attributes are set to fixed default values listed below (this holds for all bpf_tc_* APIs): protocol as ETH_P_ALL, direct action mode, chain index of 0, and class ID of 0 (this can be set by writing to the skb->tc_classid field from the BPF program). bpf_tc_detach Parameters: @hook - Cannot be NULL. Represents the hook the filter will be detached from. Requirements are same as described above in bpf_tc_attach. @opts - Cannot be NULL. The following opts must be set: * handle, priority The following opts must be unset: * prog_fd, prog_id, flags bpf_tc_query Parameters: @hook - Cannot be NULL. Represents the hook where the filter lookup will be performed. Requirements are same as described above in bpf_tc_attach(). @opts - Cannot be NULL. The following opts must be set: * handle, priority The following opts must be unset: * prog_fd, prog_id, flags The following fields will be filled by bpf_tc_query upon a successful lookup: * prog_id Some usage examples (using BPF skeleton infrastructure): BPF program (test_tc_bpf.c): #include <linux/bpf.h> #include <bpf/bpf_helpers.h> SEC("classifier") int cls(struct __sk_buff *skb) { return 0; } Userspace loader: struct test_tc_bpf *skel = NULL; int fd, r; skel = test_tc_bpf__open_and_load(); if (!skel) return -ENOMEM; fd = bpf_program__fd(skel->progs.cls); DECLARE_LIBBPF_OPTS(bpf_tc_hook, hook, .ifindex = if_nametoindex("lo"), .attach_point = BPF_TC_INGRESS); /* Create clsact qdisc */ r = bpf_tc_hook_create(&hook); if (r < 0) goto end; DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts, .prog_fd = fd); r = bpf_tc_attach(&hook, &opts); if (r < 0) goto end; /* Print the auto allocated handle and priority */ printf("Handle=%u", opts.handle); printf("Priority=%u", opts.priority); opts.prog_fd = opts.prog_id = 0; bpf_tc_detach(&hook, &opts); end: test_tc_bpf__destroy(skel); This is equivalent to doing the following using tc command line: # tc qdisc add dev lo clsact # tc filter add dev lo ingress bpf obj foo.o sec classifier da # tc filter del dev lo ingress handle <h> prio <p> bpf ... where the handle and priority can be found using: # tc filter show dev lo ingress Another example replacing a filter (extending prior example): /* We can also choose both (or one), let's try replacing an * existing filter. */ DECLARE_LIBBPF_OPTS(bpf_tc_opts, replace_opts, .handle = opts.handle, .priority = opts.priority, .prog_fd = fd); r = bpf_tc_attach(&hook, &replace_opts); if (r == -EEXIST) { /* Expected, now use BPF_TC_F_REPLACE to replace it */ replace_opts.flags = BPF_TC_F_REPLACE; return bpf_tc_attach(&hook, &replace_opts); } else if (r < 0) { return r; } /* There must be no existing filter with these * attributes, so cleanup and return an error. */ replace_opts.prog_fd = replace_opts.prog_id = 0; bpf_tc_detach(&hook, &replace_opts); return -1; To obtain info of a particular filter: /* Find info for filter with handle 1 and priority 50 */ DECLARE_LIBBPF_OPTS(bpf_tc_opts, info_opts, .handle = 1, .priority = 50); r = bpf_tc_query(&hook, &info_opts); if (r == -ENOENT) printf("Filter not found"); else if (r < 0) return r; printf("Prog ID: %u", info_opts.prog_id); return 0; Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Co-developed-by: Daniel Borkmann <daniel@iogearbox.net> # libbpf API design [ Daniel: also did major patch cleanup ] Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20210512103451.989420-3-memxor@gmail.com
2021-04-08libbpf: Add bpf_map__inner_map APIAndrii Nakryiko
The API gives access to inner map for map in map types (array or hash of map). It will be used to dynamically set max_entries in it. Signed-off-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210408061310.95877-7-yauheni.kaliuta@redhat.com
2021-03-25libbpf: Add bpf object kern_version attribute setterRafael David Tinoco
Unfortunately some distros don't have their kernel version defined accurately in <linux/version.h> due to different long term support reasons. It is important to have a way to override the bpf kern_version attribute during runtime: some old kernels might still check for kern_version attribute during bpf_prog_load(). Signed-off-by: Rafael David Tinoco <rafaeldtinoco@ubuntu.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20210323040952.2118241-1-rafaeldtinoco@ubuntu.com
2021-03-18libbpf: Add BPF static linker APIsAndrii Nakryiko
Introduce BPF static linker APIs to libbpf. BPF static linker allows to perform static linking of multiple BPF object files into a single combined resulting object file, preserving all the BPF programs, maps, global variables, etc. Data sections (.bss, .data, .rodata, .maps, maps, etc) with the same name are concatenated together. Similarly, code sections are also concatenated. All the symbols and ELF relocations are also concatenated in their respective ELF sections and are adjusted accordingly to the new object file layout. Static variables and functions are handled correctly as well, adjusting BPF instructions offsets to reflect new variable/function offset within the combined ELF section. Such relocations are referencing STT_SECTION symbols and that stays intact. Data sections in different files can have different alignment requirements, so that is taken care of as well, adjusting sizes and offsets as necessary to satisfy both old and new alignment requirements. DWARF data sections are stripped out, currently. As well as LLLVM_ADDRSIG section, which is ignored by libbpf in bpf_object__open() anyways. So, in a way, BPF static linker is an analogue to `llvm-strip -g`, which is a pretty nice property, especially if resulting .o file is then used to generate BPF skeleton. Original string sections are ignored and instead we construct our own set of unique strings using libbpf-internal `struct strset` API. To reduce the size of the patch, all the .BTF and .BTF.ext processing was moved into a separate patch. The high-level API consists of just 4 functions: - bpf_linker__new() creates an instance of BPF static linker. It accepts output filename and (currently empty) options struct; - bpf_linker__add_file() takes input filename and appends it to the already processed ELF data; it can be called multiple times, one for each BPF ELF object file that needs to be linked in; - bpf_linker__finalize() needs to be called to dump final ELF contents into the output file, specified when bpf_linker was created; after bpf_linker__finalize() is called, no more bpf_linker__add_file() and bpf_linker__finalize() calls are allowed, they will return error; - regardless of whether bpf_linker__finalize() was called or not, bpf_linker__free() will free up all the used resources. Currently, BPF static linker doesn't resolve cross-object file references (extern variables and/or functions). This will be added in the follow up patch set. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210318194036.3521577-7-andrii@kernel.org
2021-03-18libbpf: Add generic BTF type shallow copy APIAndrii Nakryiko
Add btf__add_type() API that performs shallow copy of a given BTF type from the source BTF into the destination BTF. All the information and type IDs are preserved, but all the strings encountered are added into the destination BTF and corresponding offsets are rewritten. BTF type IDs are assumed to be correct or such that will be (somehow) modified afterwards. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210318194036.3521577-6-andrii@kernel.org
2021-03-04libbpf: Add BTF_KIND_FLOAT supportIlya Leoshkevich
The logic follows that of BTF_KIND_INT most of the time. Sanitization replaces BTF_KIND_FLOATs with equally-sized empty BTF_KIND_STRUCTs on older kernels, for example, the following: [4] FLOAT 'float' size=4 becomes the following: [4] STRUCT '(anon)' size=4 vlen=0 With dwarves patch [1] and this patch, the older kernels, which were failing with the floating-point-related errors, will now start working correctly. [1] https://github.com/iii-i/dwarves/commit/btf-kind-float-v2 Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210226202256.116518-4-iii@linux.ibm.com
2020-12-14libbpf: Expose libbpf ring_buffer epoll_fdBrendan Jackman
This provides a convenient perf ringbuf -> libbpf ringbuf migration path for users of external polling systems. It is analogous to perf_buffer__epoll_fd. Signed-off-by: Brendan Jackman <jackmanb@google.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20201214113812.305274-1-jackmanb@google.com
2020-12-03libbpf: Separate XDP program load with xsk socket creationMariusz Dudek
Add support for separation of eBPF program load and xsk socket creation. This is needed for use-case when you want to privide as little privileges as possible to the data plane application that will handle xsk socket creation and incoming traffic. With this patch the data entity container can be run with only CAP_NET_RAW capability to fulfill its purpose of creating xsk socket and handling packages. In case your umem is larger or equal process limit for MEMLOCK you need either increase the limit or CAP_IPC_LOCK capability. To resolve privileges issue two APIs are introduced: - xsk_setup_xdp_prog - loads the built in XDP program. It can also return xsks_map_fd which is needed by unprivileged process to update xsks_map with AF_XDP socket "fd" - xsk_socket__update_xskmap - inserts an AF_XDP socket into an xskmap for a particular xsk_socket Signed-off-by: Mariusz Dudek <mariuszx.dudek@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Magnus Karlsson <magnus.karlsson@intel.com> Link: https://lore.kernel.org/bpf/20201203090546.11976-2-mariuszx.dudek@intel.com
2020-12-03libbpf: Add base BTF accessorAndrii Nakryiko
Add ability to get base BTF. It can be also used to check if BTF is split BTF. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20201202065244.530571-3-andrii@kernel.org
2020-11-05libbpf: Implement basic split BTF supportAndrii Nakryiko
Support split BTF operation, in which one BTF (base BTF) provides basic set of types and strings, while another one (split BTF) builds on top of base's types and strings and adds its own new types and strings. From API standpoint, the fact that the split BTF is built on top of the base BTF is transparent. Type numeration is transparent. If the base BTF had last type ID #N, then all types in the split BTF start at type ID N+1. Any type in split BTF can reference base BTF types, but not vice versa. Programmatically construction of a split BTF on top of a base BTF is supported: one can create an empty split BTF with btf__new_empty_split() and pass base BTF as an input, or pass raw binary data to btf__new_split(), or use btf__parse_xxx_split() variants to get initial set of split types/strings from the ELF file with .BTF section. String offsets are similarly transparent and are a logical continuation of base BTF's strings. When building BTF programmatically and adding a new string (explicitly with btf__add_str() or implicitly through appending new types/members), string-to-be-added would first be looked up from the base BTF's string section and re-used if it's there. If not, it will be looked up and/or added to the split BTF string section. Similarly to type IDs, types in split BTF can refer to strings from base BTF absolutely transparently (but not vice versa, of course, because base BTF doesn't "know" about existence of split BTF). Internal type index is slightly adjusted to be zero-indexed, ignoring a fake [0] VOID type. This allows to handle split/base BTF type lookups transparently by using btf->start_id type ID offset, which is always 1 for base/non-split BTF and equals btf__get_nr_types(base_btf) + 1 for the split BTF. BTF deduplication is not yet supported for split BTF and support for it will be added in separate patch. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20201105043402.2530976-5-andrii@kernel.org
2020-09-29libbpf: Add support for freplace attachment in bpf_link_createToke Høiland-Jørgensen
This adds support for supplying a target btf ID for the bpf_link_create() operation, and adds a new bpf_program__attach_freplace() high-level API for attaching freplace functions with a target. Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/160138355387.48470.18026176785351166890.stgit@toke.dk
2020-09-29libbpf: Support BTF loading and raw data output in both endiannessAndrii Nakryiko
Teach BTF to recognized wrong endianness and transparently convert it internally to host endianness. Original endianness of BTF will be preserved and used during btf__get_raw_data() to convert resulting raw data to the same endianness and a source raw_data. This means that little-endian host can parse big-endian BTF with no issues, all the type data will be presented to the client application in native endianness, but when it's time for emitting BTF to persist it in a file (e.g., after BTF deduplication), original non-native endianness will be preserved and stored. It's possible to query original endianness of BTF data with new btf__endianness() API. It's also possible to override desired output endianness with btf__set_endianness(), so that if application needs to load, say, big-endian BTF and store it as little-endian BTF, it's possible to manually override this. If btf__set_endianness() was used to change endianness, btf__endianness() will reflect overridden endianness. Given there are no known use cases for supporting cross-endianness for .BTF.ext, loading .BTF.ext in non-native endianness is not supported. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200929043046.1324350-3-andriin@fb.com
2020-09-28libbpf: Add btf__str_by_offset() as a more generic variant of name_by_offsetAndrii Nakryiko
BTF strings are used not just for names, they can be arbitrary strings used for CO-RE relocations, line/func infos, etc. Thus "name_by_offset" terminology is too specific and might be misleading. Instead, introduce btf__str_by_offset() API which uses generic string terminology. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200929020533.711288-3-andriin@fb.com
2020-09-28libbpf: Add BTF writing APIsAndrii Nakryiko
Add APIs for appending new BTF types at the end of BTF object. Each BTF kind has either one API of the form btf__add_<kind>(). For types that have variable amount of additional items (struct/union, enum, func_proto, datasec), additional API is provided to emit each such item. E.g., for emitting a struct, one would use the following sequence of API calls: btf__add_struct(...); btf__add_field(...); ... btf__add_field(...); Each btf__add_field() will ensure that the last BTF type is of STRUCT or UNION kind and will automatically increment that type's vlen field. All the strings are provided as C strings (const char *), not a string offset. This significantly improves usability of BTF writer APIs. All such strings will be automatically appended to string section or existing string will be re-used, if such string was already added previously. Each API attempts to do all the reasonable validations, like enforcing non-empty names for entities with required names, proper value bounds, various bit offset restrictions, etc. Type ID validation is minimal because it's possible to emit a type that refers to type that will be emitted later, so libbpf has no way to enforce such cases. User must be careful to properly emit all the necessary types and specify type IDs that will be valid in the finally generated BTF. Each of btf__add_<kind>() APIs return new type ID on success or negative value on error. APIs like btf__add_field() that emit additional items return zero on success and negative value on error. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200929020533.711288-2-andriin@fb.com
2020-09-28libbpf: Add btf__new_empty() to create an empty BTF objectAndrii Nakryiko
Add an ability to create an empty BTF object from scratch. This is going to be used by pahole for BTF encoding. And also by selftest for convenient creation of BTF objects. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200926011357.2366158-7-andriin@fb.com
2020-09-28libbpf: Allow modification of BTF and add btf__add_str APIAndrii Nakryiko
Allow internal BTF representation to switch from default read-only mode, in which raw BTF data is a single non-modifiable block of memory with BTF header, types, and strings layed out sequentially and contiguously in memory, into a writable representation with types and strings data split out into separate memory regions, that can be dynamically expanded. Such writable internal representation is transparent to users of libbpf APIs, but allows to append new types and strings at the end of BTF, which is a typical use case when generating BTF programmatically. All the basic guarantees of BTF types and strings layout is preserved, i.e., user can get `struct btf_type *` pointer and read it directly. Such btf_type pointers might be invalidated if BTF is modified, so some care is required in such mixed read/write scenarios. Switch from read-only to writable configuration happens automatically the first time when user attempts to modify BTF by either adding a new type or new string. It is still possible to get raw BTF data, which is a single piece of memory that can be persisted in ELF section or into a file as raw BTF. Such raw data memory is also still owned by BTF and will be freed either when BTF object is freed or if another modification to BTF happens, as any modification invalidates BTF raw representation. This patch adds the first two BTF manipulation APIs: btf__add_str(), which allows to add arbitrary strings to BTF string section, and btf__find_str() which allows to find existing string offset, but not add it if it's missing. All the added strings are automatically deduplicated. This is achieved by maintaining an additional string lookup index for all unique strings. Such index is built when BTF is switched to modifiable mode. If at that time BTF strings section contained duplicate strings, they are not de-duplicated. This is done specifically to not modify the existing content of BTF (types, their string offsets, etc), which can cause confusion and is especially important property if there is struct btf_ext associated with struct btf. By following this "imperfect deduplication" process, btf_ext is kept consitent and correct. If deduplication of strings is necessary, it can be forced by doing BTF deduplication, at which point all the strings will be eagerly deduplicated and all string offsets both in struct btf and struct btf_ext will be updated. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200926011357.2366158-6-andriin@fb.com
2020-09-28libbpf: Support test run of raw tracepoint programsSong Liu
Add bpf_prog_test_run_opts() with support of new fields in bpf_attr.test, namely, flags and cpu. Also extend _opts operations to support outputs via opts. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200925205432.1777-3-songliubraving@fb.com
2020-09-15libbpf: Add BPF_PROG_BIND_MAP syscall and use it on .rodata sectionYiFei Zhu
The patch adds a simple wrapper bpf_prog_bind_map around the syscall. When the libbpf tries to load a program, it will probe the kernel for the support of this syscall and unconditionally bind .rodata section to the program. Signed-off-by: YiFei Zhu <zhuyifei@google.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Cc: YiFei Zhu <zhuyifei1999@gmail.com> Link: https://lore.kernel.org/bpf/20200915234543.3220146-4-sdf@google.com
2020-09-03libbpf: Deprecate notion of BPF program "title" in favor of "section name"Andrii Nakryiko
BPF program title is ambigious and misleading term. It is ELF section name, so let's just call it that and deprecate bpf_program__title() API in favor of bpf_program__section_name(). Additionally, using bpf_object__find_program_by_title() is now inherently dangerous and ambiguous, as multiple BPF program can have the same section name. So deprecate this API as well and recommend to switch to non-ambiguous bpf_object__find_program_by_name(). Internally, clean up usage and mis-usage of BPF program section name for denoting BPF program name. Shorten the field name to prog->sec_name to be consistent with all other prog->sec_* variables. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200903203542.15944-11-andriin@fb.com
2020-08-31libbpf: Support shared umems between queues and devicesMagnus Karlsson
Add support for shared umems between hardware queues and devices to the AF_XDP part of libbpf. This so that zero-copy can be achieved in applications that want to send and receive packets between HW queues on one device or between different devices/netdevs. In order to create sockets that share a umem between hardware queues and devices, a new function has been added called xsk_socket__create_shared(). It takes the same arguments as xsk_socket_create() plus references to a fill ring and a completion ring. So for every socket that share a umem, you need to have one more set of fill and completion rings. This in order to maintain the single-producer single-consumer semantics of the rings. You can create all the sockets via the new xsk_socket__create_shared() call, or create the first one with xsk_socket__create() and the rest with xsk_socket__create_shared(). Both methods work. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Björn Töpel <bjorn.topel@intel.com> Link: https://lore.kernel.org/bpf/1598603189-32145-14-git-send-email-magnus.karlsson@intel.com
2020-08-21libbpf: Add perf_buffer APIs for better integration with outside epoll loopAndrii Nakryiko
Add a set of APIs to perf_buffer manage to allow applications to integrate perf buffer polling into existing epoll-based infrastructure. One example is applications using libevent already and wanting to plug perf_buffer polling, instead of relying on perf_buffer__poll() and waste an extra thread to do it. But perf_buffer is still extremely useful to set up and consume perf buffer rings even for such use cases. So to accomodate such new use cases, add three new APIs: - perf_buffer__buffer_cnt() returns number of per-CPU buffers maintained by given instance of perf_buffer manager; - perf_buffer__buffer_fd() returns FD of perf_event corresponding to a specified per-CPU buffer; this FD is then polled independently; - perf_buffer__consume_buffer() consumes data from single per-CPU buffer, identified by its slot index. To support a simpler, but less efficient, way to integrate perf_buffer into external polling logic, also expose underlying epoll FD through perf_buffer__epoll_fd() API. It will need to be followed by perf_buffer__poll(), wasting extra syscall, or perf_buffer__consume(), wasting CPU to iterate buffers with no data. But could be simpler and more convenient for some cases. These APIs allow for great flexiblity, but do not sacrifice general usability of perf_buffer. Also exercise and check new APIs in perf_buffer selftest. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Link: https://lore.kernel.org/bpf/20200821165927.849538-1-andriin@fb.com