diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c index 4a2867439ab7..d6508dde4808 100644 --- a/tools/bpf/bpftool/feature.c +++ b/tools/bpf/bpftool/feature.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) /* Copyright (c) 2019 Netronome Systems, Inc. */ +#include #include #include #include @@ -11,6 +12,7 @@ #include #include +#include #include "main.h" @@ -83,6 +85,17 @@ print_start_section(const char *json_title, const char *plain_title) } } +static void +print_end_then_start_section(const char *json_title, const char *plain_title) +{ + if (json_output) + jsonw_end_object(json_wtr); + else + printf("\n"); + + print_start_section(json_title, plain_title); +} + /* Probing functions */ static int read_procfs(const char *path) @@ -403,9 +416,33 @@ static bool probe_bpf_syscall(void) return res; } +static void probe_prog_type(enum bpf_prog_type prog_type, bool *supported_types) +{ + const char *plain_comment = "eBPF program_type "; + char feat_name[128], plain_desc[128]; + size_t maxlen; + bool res; + + res = bpf_probe_prog_type(prog_type, 0); + + supported_types[prog_type] |= res; + + maxlen = sizeof(plain_desc) - strlen(plain_comment) - 1; + if (strlen(prog_type_name[prog_type]) > maxlen) { + p_info("program type name too long"); + return; + } + + sprintf(feat_name, "have_%s_prog_type", prog_type_name[prog_type]); + sprintf(plain_desc, "%s%s", plain_comment, prog_type_name[prog_type]); + print_bool_feature(feat_name, plain_desc, res); +} + static int do_probe(int argc, char **argv) { enum probe_component target = COMPONENT_UNSPEC; + bool supported_types[128] = {}; + unsigned int i; /* Detection assumes user has sufficient privileges (CAP_SYS_ADMIN). * Let's approximate, and restrict usage to root user only. @@ -460,8 +497,17 @@ static int do_probe(int argc, char **argv) print_start_section("syscall_config", "Scanning system call availability..."); - probe_bpf_syscall(); + if (!probe_bpf_syscall()) + /* bpf() syscall unavailable, don't probe other BPF features */ + goto exit_close_json; + print_end_then_start_section("program_types", + "Scanning eBPF program types..."); + + for (i = BPF_PROG_TYPE_UNSPEC + 1; i < ARRAY_SIZE(prog_type_name); i++) + probe_prog_type(i, supported_types); + +exit_close_json: if (json_output) { /* End current "section" of probes */ jsonw_end_object(json_wtr); diff --git a/tools/lib/bpf/Build b/tools/lib/bpf/Build index 197b40f5b5c6..bfd9bfc82c3b 100644 --- a/tools/lib/bpf/Build +++ b/tools/lib/bpf/Build @@ -1 +1 @@ -libbpf-y := libbpf.o bpf.o nlattr.o btf.o libbpf_errno.o str_error.o netlink.o bpf_prog_linfo.o +libbpf-y := libbpf.o bpf.o nlattr.o btf.o libbpf_errno.o str_error.o netlink.o bpf_prog_linfo.o libbpf_probes.o diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index 5f68d7b75215..8e63821109ab 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -355,6 +355,17 @@ LIBBPF_API const struct bpf_line_info * bpf_prog_linfo__lfind(const struct bpf_prog_linfo *prog_linfo, __u32 insn_off, __u32 nr_skip); +/* + * Probe for supported system features + * + * Note that running many of these probes in a short amount of time can cause + * the kernel to reach the maximal size of lockable memory allowed for the + * user, causing subsequent probes to fail. In this case, the caller may want + * to adjust that limit with setrlimit(). + */ +LIBBPF_API bool bpf_probe_prog_type(enum bpf_prog_type prog_type, + __u32 ifindex); + #ifdef __cplusplus } /* extern "C" */ #endif diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index cd02cd4e2cc3..c7ec3ffa24e9 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -124,3 +124,8 @@ LIBBPF_0.0.1 { local: *; }; + +LIBBPF_0.0.2 { + global: + bpf_probe_prog_type; +} LIBBPF_0.0.1; diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c new file mode 100644 index 000000000000..056c0c186f2a --- /dev/null +++ b/tools/lib/bpf/libbpf_probes.c @@ -0,0 +1,95 @@ +// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) +/* Copyright (c) 2019 Netronome Systems, Inc. */ + +#include +#include +#include + +#include +#include + +#include "bpf.h" +#include "libbpf.h" + +static int get_kernel_version(void) +{ + int version, subversion, patchlevel; + struct utsname utsn; + + /* Return 0 on failure, and attempt to probe with empty kversion */ + if (uname(&utsn)) + return 0; + + if (sscanf(utsn.release, "%d.%d.%d", + &version, &subversion, &patchlevel) != 3) + return 0; + + return (version << 16) + (subversion << 8) + patchlevel; +} + +static void +probe_load(enum bpf_prog_type prog_type, const struct bpf_insn *insns, + size_t insns_cnt, char *buf, size_t buf_len, __u32 ifindex) +{ + struct bpf_load_program_attr xattr = {}; + int fd; + + switch (prog_type) { + case BPF_PROG_TYPE_CGROUP_SOCK_ADDR: + xattr.expected_attach_type = BPF_CGROUP_INET4_CONNECT; + break; + case BPF_PROG_TYPE_KPROBE: + xattr.kern_version = get_kernel_version(); + break; + case BPF_PROG_TYPE_UNSPEC: + case BPF_PROG_TYPE_SOCKET_FILTER: + case BPF_PROG_TYPE_SCHED_CLS: + case BPF_PROG_TYPE_SCHED_ACT: + case BPF_PROG_TYPE_TRACEPOINT: + case BPF_PROG_TYPE_XDP: + case BPF_PROG_TYPE_PERF_EVENT: + case BPF_PROG_TYPE_CGROUP_SKB: + case BPF_PROG_TYPE_CGROUP_SOCK: + case BPF_PROG_TYPE_LWT_IN: + case BPF_PROG_TYPE_LWT_OUT: + case BPF_PROG_TYPE_LWT_XMIT: + case BPF_PROG_TYPE_SOCK_OPS: + case BPF_PROG_TYPE_SK_SKB: + case BPF_PROG_TYPE_CGROUP_DEVICE: + case BPF_PROG_TYPE_SK_MSG: + case BPF_PROG_TYPE_RAW_TRACEPOINT: + case BPF_PROG_TYPE_LWT_SEG6LOCAL: + case BPF_PROG_TYPE_LIRC_MODE2: + case BPF_PROG_TYPE_SK_REUSEPORT: + case BPF_PROG_TYPE_FLOW_DISSECTOR: + default: + break; + } + + xattr.prog_type = prog_type; + xattr.insns = insns; + xattr.insns_cnt = insns_cnt; + xattr.license = "GPL"; + xattr.prog_ifindex = ifindex; + + fd = bpf_load_program_xattr(&xattr, buf, buf_len); + if (fd >= 0) + close(fd); +} + +bool bpf_probe_prog_type(enum bpf_prog_type prog_type, __u32 ifindex) +{ + struct bpf_insn insns[2] = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN() + }; + + if (ifindex && prog_type == BPF_PROG_TYPE_SCHED_CLS) + /* nfp returns -EINVAL on exit(0) with TC offload */ + insns[0].imm = 2; + + errno = 0; + probe_load(prog_type, insns, ARRAY_SIZE(insns), NULL, 0, ifindex); + + return errno != EINVAL && errno != EOPNOTSUPP; +}