| // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) |
| /* Copyright (c) 2019 Netronome Systems, Inc. */ |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <string.h> |
| #include <stdlib.h> |
| #include <unistd.h> |
| #include <net/if.h> |
| #include <sys/utsname.h> |
| |
| #include <linux/btf.h> |
| #include <linux/filter.h> |
| #include <linux/kernel.h> |
| |
| #include "bpf.h" |
| #include "libbpf.h" |
| #include "libbpf_internal.h" |
| |
| static int probe_prog_load(enum bpf_prog_type prog_type, |
| const struct bpf_insn *insns, size_t insns_cnt, |
| char *log_buf, size_t log_buf_sz) |
| { |
| LIBBPF_OPTS(bpf_prog_load_opts, opts, |
| .log_buf = log_buf, |
| .log_size = log_buf_sz, |
| .log_level = log_buf ? 1 : 0, |
| ); |
| int fd, err, exp_err = 0; |
| const char *exp_msg = NULL; |
| char buf[4096]; |
| |
| switch (prog_type) { |
| case BPF_PROG_TYPE_CGROUP_SOCK_ADDR: |
| opts.expected_attach_type = BPF_CGROUP_INET4_CONNECT; |
| break; |
| case BPF_PROG_TYPE_CGROUP_SOCKOPT: |
| opts.expected_attach_type = BPF_CGROUP_GETSOCKOPT; |
| break; |
| case BPF_PROG_TYPE_SK_LOOKUP: |
| opts.expected_attach_type = BPF_SK_LOOKUP; |
| break; |
| case BPF_PROG_TYPE_KPROBE: |
| opts.kern_version = get_kernel_version(); |
| break; |
| case BPF_PROG_TYPE_LIRC_MODE2: |
| opts.expected_attach_type = BPF_LIRC_MODE2; |
| break; |
| case BPF_PROG_TYPE_TRACING: |
| case BPF_PROG_TYPE_LSM: |
| opts.log_buf = buf; |
| opts.log_size = sizeof(buf); |
| opts.log_level = 1; |
| if (prog_type == BPF_PROG_TYPE_TRACING) |
| opts.expected_attach_type = BPF_TRACE_FENTRY; |
| else |
| opts.expected_attach_type = BPF_MODIFY_RETURN; |
| opts.attach_btf_id = 1; |
| |
| exp_err = -EINVAL; |
| exp_msg = "attach_btf_id 1 is not a function"; |
| break; |
| case BPF_PROG_TYPE_EXT: |
| opts.log_buf = buf; |
| opts.log_size = sizeof(buf); |
| opts.log_level = 1; |
| opts.attach_btf_id = 1; |
| |
| exp_err = -EINVAL; |
| exp_msg = "Cannot replace kernel functions"; |
| break; |
| case BPF_PROG_TYPE_SYSCALL: |
| opts.prog_flags = BPF_F_SLEEPABLE; |
| break; |
| case BPF_PROG_TYPE_STRUCT_OPS: |
| exp_err = -524; /* -ENOTSUPP */ |
| 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_RAW_TRACEPOINT_WRITABLE: |
| case BPF_PROG_TYPE_LWT_SEG6LOCAL: |
| case BPF_PROG_TYPE_SK_REUSEPORT: |
| case BPF_PROG_TYPE_FLOW_DISSECTOR: |
| case BPF_PROG_TYPE_CGROUP_SYSCTL: |
| break; |
| default: |
| return -EOPNOTSUPP; |
| } |
| |
| fd = bpf_prog_load(prog_type, NULL, "GPL", insns, insns_cnt, &opts); |
| err = -errno; |
| if (fd >= 0) |
| close(fd); |
| if (exp_err) { |
| if (fd >= 0 || err != exp_err) |
| return 0; |
| if (exp_msg && !strstr(buf, exp_msg)) |
| return 0; |
| return 1; |
| } |
| return fd >= 0 ? 1 : 0; |
| } |
| |
| int libbpf_probe_bpf_prog_type(enum bpf_prog_type prog_type, const void *opts) |
| { |
| struct bpf_insn insns[] = { |
| BPF_MOV64_IMM(BPF_REG_0, 0), |
| BPF_EXIT_INSN() |
| }; |
| const size_t insn_cnt = ARRAY_SIZE(insns); |
| int ret; |
| |
| if (opts) |
| return libbpf_err(-EINVAL); |
| |
| ret = probe_prog_load(prog_type, insns, insn_cnt, NULL, 0); |
| return libbpf_err(ret); |
| } |
| |
| int libbpf__load_raw_btf(const char *raw_types, size_t types_len, |
| const char *str_sec, size_t str_len) |
| { |
| struct btf_header hdr = { |
| .magic = BTF_MAGIC, |
| .version = BTF_VERSION, |
| .hdr_len = sizeof(struct btf_header), |
| .type_len = types_len, |
| .str_off = types_len, |
| .str_len = str_len, |
| }; |
| int btf_fd, btf_len; |
| __u8 *raw_btf; |
| |
| btf_len = hdr.hdr_len + hdr.type_len + hdr.str_len; |
| raw_btf = malloc(btf_len); |
| if (!raw_btf) |
| return -ENOMEM; |
| |
| memcpy(raw_btf, &hdr, sizeof(hdr)); |
| memcpy(raw_btf + hdr.hdr_len, raw_types, hdr.type_len); |
| memcpy(raw_btf + hdr.hdr_len + hdr.type_len, str_sec, hdr.str_len); |
| |
| btf_fd = bpf_btf_load(raw_btf, btf_len, NULL); |
| |
| free(raw_btf); |
| return btf_fd; |
| } |
| |
| static int load_local_storage_btf(void) |
| { |
| const char strs[] = "\0bpf_spin_lock\0val\0cnt\0l"; |
| /* struct bpf_spin_lock { |
| * int val; |
| * }; |
| * struct val { |
| * int cnt; |
| * struct bpf_spin_lock l; |
| * }; |
| */ |
| __u32 types[] = { |
| /* int */ |
| BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */ |
| /* struct bpf_spin_lock */ /* [2] */ |
| BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), 4), |
| BTF_MEMBER_ENC(15, 1, 0), /* int val; */ |
| /* struct val */ /* [3] */ |
| BTF_TYPE_ENC(15, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 2), 8), |
| BTF_MEMBER_ENC(19, 1, 0), /* int cnt; */ |
| BTF_MEMBER_ENC(23, 2, 32),/* struct bpf_spin_lock l; */ |
| }; |
| |
| return libbpf__load_raw_btf((char *)types, sizeof(types), |
| strs, sizeof(strs)); |
| } |
| |
| static int probe_map_create(enum bpf_map_type map_type) |
| { |
| LIBBPF_OPTS(bpf_map_create_opts, opts); |
| int key_size, value_size, max_entries; |
| __u32 btf_key_type_id = 0, btf_value_type_id = 0; |
| int fd = -1, btf_fd = -1, fd_inner = -1, exp_err = 0, err = 0; |
| |
| key_size = sizeof(__u32); |
| value_size = sizeof(__u32); |
| max_entries = 1; |
| |
| switch (map_type) { |
| case BPF_MAP_TYPE_STACK_TRACE: |
| value_size = sizeof(__u64); |
| break; |
| case BPF_MAP_TYPE_LPM_TRIE: |
| key_size = sizeof(__u64); |
| value_size = sizeof(__u64); |
| opts.map_flags = BPF_F_NO_PREALLOC; |
| break; |
| case BPF_MAP_TYPE_CGROUP_STORAGE: |
| case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE: |
| key_size = sizeof(struct bpf_cgroup_storage_key); |
| value_size = sizeof(__u64); |
| max_entries = 0; |
| break; |
| case BPF_MAP_TYPE_QUEUE: |
| case BPF_MAP_TYPE_STACK: |
| key_size = 0; |
| break; |
| case BPF_MAP_TYPE_SK_STORAGE: |
| case BPF_MAP_TYPE_INODE_STORAGE: |
| case BPF_MAP_TYPE_TASK_STORAGE: |
| btf_key_type_id = 1; |
| btf_value_type_id = 3; |
| value_size = 8; |
| max_entries = 0; |
| opts.map_flags = BPF_F_NO_PREALLOC; |
| btf_fd = load_local_storage_btf(); |
| if (btf_fd < 0) |
| return btf_fd; |
| break; |
| case BPF_MAP_TYPE_RINGBUF: |
| case BPF_MAP_TYPE_USER_RINGBUF: |
| key_size = 0; |
| value_size = 0; |
| max_entries = 4096; |
| break; |
| case BPF_MAP_TYPE_STRUCT_OPS: |
| /* we'll get -ENOTSUPP for invalid BTF type ID for struct_ops */ |
| opts.btf_vmlinux_value_type_id = 1; |
| exp_err = -524; /* -ENOTSUPP */ |
| break; |
| case BPF_MAP_TYPE_BLOOM_FILTER: |
| key_size = 0; |
| max_entries = 1; |
| break; |
| case BPF_MAP_TYPE_HASH: |
| case BPF_MAP_TYPE_ARRAY: |
| case BPF_MAP_TYPE_PROG_ARRAY: |
| case BPF_MAP_TYPE_PERF_EVENT_ARRAY: |
| case BPF_MAP_TYPE_PERCPU_HASH: |
| case BPF_MAP_TYPE_PERCPU_ARRAY: |
| case BPF_MAP_TYPE_CGROUP_ARRAY: |
| case BPF_MAP_TYPE_LRU_HASH: |
| case BPF_MAP_TYPE_LRU_PERCPU_HASH: |
| case BPF_MAP_TYPE_ARRAY_OF_MAPS: |
| case BPF_MAP_TYPE_HASH_OF_MAPS: |
| case BPF_MAP_TYPE_DEVMAP: |
| case BPF_MAP_TYPE_DEVMAP_HASH: |
| case BPF_MAP_TYPE_SOCKMAP: |
| case BPF_MAP_TYPE_CPUMAP: |
| case BPF_MAP_TYPE_XSKMAP: |
| case BPF_MAP_TYPE_SOCKHASH: |
| case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY: |
| break; |
| case BPF_MAP_TYPE_UNSPEC: |
| default: |
| return -EOPNOTSUPP; |
| } |
| |
| if (map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS || |
| map_type == BPF_MAP_TYPE_HASH_OF_MAPS) { |
| fd_inner = bpf_map_create(BPF_MAP_TYPE_HASH, NULL, |
| sizeof(__u32), sizeof(__u32), 1, NULL); |
| if (fd_inner < 0) |
| goto cleanup; |
| |
| opts.inner_map_fd = fd_inner; |
| } |
| |
| if (btf_fd >= 0) { |
| opts.btf_fd = btf_fd; |
| opts.btf_key_type_id = btf_key_type_id; |
| opts.btf_value_type_id = btf_value_type_id; |
| } |
| |
| fd = bpf_map_create(map_type, NULL, key_size, value_size, max_entries, &opts); |
| err = -errno; |
| |
| cleanup: |
| if (fd >= 0) |
| close(fd); |
| if (fd_inner >= 0) |
| close(fd_inner); |
| if (btf_fd >= 0) |
| close(btf_fd); |
| |
| if (exp_err) |
| return fd < 0 && err == exp_err ? 1 : 0; |
| else |
| return fd >= 0 ? 1 : 0; |
| } |
| |
| int libbpf_probe_bpf_map_type(enum bpf_map_type map_type, const void *opts) |
| { |
| int ret; |
| |
| if (opts) |
| return libbpf_err(-EINVAL); |
| |
| ret = probe_map_create(map_type); |
| return libbpf_err(ret); |
| } |
| |
| int libbpf_probe_bpf_helper(enum bpf_prog_type prog_type, enum bpf_func_id helper_id, |
| const void *opts) |
| { |
| struct bpf_insn insns[] = { |
| BPF_EMIT_CALL((__u32)helper_id), |
| BPF_EXIT_INSN(), |
| }; |
| const size_t insn_cnt = ARRAY_SIZE(insns); |
| char buf[4096]; |
| int ret; |
| |
| if (opts) |
| return libbpf_err(-EINVAL); |
| |
| /* we can't successfully load all prog types to check for BPF helper |
| * support, so bail out with -EOPNOTSUPP error |
| */ |
| switch (prog_type) { |
| case BPF_PROG_TYPE_TRACING: |
| case BPF_PROG_TYPE_EXT: |
| case BPF_PROG_TYPE_LSM: |
| case BPF_PROG_TYPE_STRUCT_OPS: |
| return -EOPNOTSUPP; |
| default: |
| break; |
| } |
| |
| buf[0] = '\0'; |
| ret = probe_prog_load(prog_type, insns, insn_cnt, buf, sizeof(buf)); |
| if (ret < 0) |
| return libbpf_err(ret); |
| |
| /* If BPF verifier doesn't recognize BPF helper ID (enum bpf_func_id) |
| * at all, it will emit something like "invalid func unknown#181". |
| * If BPF verifier recognizes BPF helper but it's not supported for |
| * given BPF program type, it will emit "unknown func bpf_sys_bpf#166". |
| * In both cases, provided combination of BPF program type and BPF |
| * helper is not supported by the kernel. |
| * In all other cases, probe_prog_load() above will either succeed (e.g., |
| * because BPF helper happens to accept no input arguments or it |
| * accepts one input argument and initial PTR_TO_CTX is fine for |
| * that), or we'll get some more specific BPF verifier error about |
| * some unsatisfied conditions. |
| */ |
| if (ret == 0 && (strstr(buf, "invalid func ") || strstr(buf, "unknown func "))) |
| return 0; |
| return 1; /* assume supported */ |
| } |