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Thu, 03 Jul 2025 13:48:37 -0700 (PDT) Received: from localhost ([2a03:2880:30ff:1::]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-60fcb0c892csm272517a12.38.2025.07.03.13.48.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Jul 2025 13:48:37 -0700 (PDT) From: Kumar Kartikeya Dwivedi To: bpf@vger.kernel.org Cc: Andrii Nakryiko , Eduard Zingerman , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Emil Tsalapatis , Barret Rhoden , Matt Bobrowski , kkd@meta.com, kernel-team@meta.com Subject: [PATCH bpf-next v5 10/12] libbpf: Introduce bpf_prog_stream_read() API Date: Thu, 3 Jul 2025 13:48:16 -0700 Message-ID: <20250703204818.925464-11-memxor@gmail.com> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20250703204818.925464-1-memxor@gmail.com> References: <20250703204818.925464-1-memxor@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3150; h=from:subject; bh=iBCaZSNhEt8VX4yj84U+4N8Bh/c2LX+LaCdo41sJJv0=; b=owEBbQKS/ZANAwAIAUzgyIZIvxHKAcsmYgBoZudM0cih2+u1qHSe9PZDmGtJPIM6jHDEAWB561WT dPVD8cyJAjMEAAEIAB0WIQRLvip+Buz51YI8YRFM4MiGSL8RygUCaGbnTAAKCRBM4MiGSL8RyjYKD/ 9OWWtzxSuE3izHcMEuUSrBBzilsK5jtk7OEyYbauUK6SiwftymXwzmIjE94woX9hWJ5XCg9XbQgjB/ uk8SDxZywwXAqgwXz+NPECuU04jpLqGcwmuIbLdEVUp+Ly+dN0coQcQTOwv+/ezTWB2peDQTMrcBXY cWMP9FDJRw9g04wJbWnZnAX/yS6NfWmwJRGzdNdOAvayPze0p5Q1K16g0Yo2Fu7FLHO37VORVrOjVy iXG1nIPa/EOBpRgXM87JMHdxR2AWmJImy5TwEtwddmTeLGDK+J7ETTzV65Mh7pGdNqe5hTMtKQAnVD Q4Ss+m6vfye6DsbpMZ/AoRo0U8AKw1F0PaJ87ce65TJxxbtHqBypZWgRTHaLrDUyp73XVT0NclaxxF aaR91sNGQndcVUgLOMhqTw8IrNkt6TC8+MOd4Nl9+wEQ5mQSgkyWTcxggCjUurrzGUeQmaTNAaXmAf YivMn4uSiBVHzbG8i7Y8sPaHdLckUyfV0T2Y4HyI8T/IesXNxVPHidNmcq2fYpn3/8UtqXJ8LkjrAC O5SmBD88LKRmkmv6ZKmPj0n/ux2hpT423Sgbb4QHdXDTieR3w3KX9pKlLNSsmlEkhtsBGJnDD8uiO9 FakSLtPvIGVYNa0SnH4H/F3CeYdzsX3bj+I+hQYCMS997qJN3GUixAAnO90g== X-Developer-Key: i=memxor@gmail.com; a=openpgp; fpr=4BBE2A7E06ECF9D5823C61114CE0C88648BF11CA Content-Transfer-Encoding: 8bit Introduce a libbpf API so that users can read data from a given BPF stream for a BPF prog fd. For now, only the low-level syscall wrapper is provided, we can add a bpf_program__* accessor as a follow up if needed. Acked-by: Andrii Nakryiko Acked-by: Eduard Zingerman Signed-off-by: Kumar Kartikeya Dwivedi --- tools/lib/bpf/bpf.c | 20 ++++++++++++++++++++ tools/lib/bpf/bpf.h | 21 +++++++++++++++++++++ tools/lib/bpf/libbpf.map | 1 + 3 files changed, 42 insertions(+) diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 6eb421ccf91b..ab40dbf9f020 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -1375,3 +1375,23 @@ int bpf_token_create(int bpffs_fd, struct bpf_token_create_opts *opts) fd = sys_bpf_fd(BPF_TOKEN_CREATE, &attr, attr_sz); return libbpf_err_errno(fd); } + +int bpf_prog_stream_read(int prog_fd, __u32 stream_id, void *buf, __u32 buf_len, + struct bpf_prog_stream_read_opts *opts) +{ + const size_t attr_sz = offsetofend(union bpf_attr, prog_stream_read); + union bpf_attr attr; + int err; + + if (!OPTS_VALID(opts, bpf_prog_stream_read_opts)) + return libbpf_err(-EINVAL); + + memset(&attr, 0, attr_sz); + attr.prog_stream_read.stream_buf = ptr_to_u64(buf); + attr.prog_stream_read.stream_buf_len = buf_len; + attr.prog_stream_read.stream_id = stream_id; + attr.prog_stream_read.prog_fd = prog_fd; + + err = sys_bpf(BPF_PROG_STREAM_READ_BY_FD, &attr, attr_sz); + return libbpf_err_errno(err); +} diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index 1342564214c8..7252150e7ad3 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -709,6 +709,27 @@ struct bpf_token_create_opts { LIBBPF_API int bpf_token_create(int bpffs_fd, struct bpf_token_create_opts *opts); +struct bpf_prog_stream_read_opts { + size_t sz; + size_t :0; +}; +#define bpf_prog_stream_read_opts__last_field sz +/** + * @brief **bpf_prog_stream_read** reads data from the BPF stream of a given BPF + * program. + * + * @param prog_fd FD for the BPF program whose BPF stream is to be read. + * @param stream_id ID of the BPF stream to be read. + * @param buf Buffer to read data into from the BPF stream. + * @param buf_len Maximum number of bytes to read from the BPF stream. + * @param opts optional options, can be NULL + * + * @return The number of bytes read, on success; negative error code, otherwise + * (errno is also set to the error code) + */ +LIBBPF_API int bpf_prog_stream_read(int prog_fd, __u32 stream_id, void *buf, __u32 buf_len, + struct bpf_prog_stream_read_opts *opts); + #ifdef __cplusplus } /* extern "C" */ #endif diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index c7fc0bde5648..1bbf77326420 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -437,6 +437,7 @@ LIBBPF_1.6.0 { bpf_linker__add_fd; bpf_linker__new_fd; bpf_object__prepare; + bpf_prog_stream_read; bpf_program__attach_cgroup_opts; bpf_program__func_info; bpf_program__func_info_cnt; -- 2.47.1