| /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ |
| #ifndef __BPF_HELPERS__ |
| #define __BPF_HELPERS__ |
| |
| /* |
| * Note that bpf programs need to include either |
| * vmlinux.h (auto-generated from BTF) or linux/types.h |
| * in advance since bpf_helper_defs.h uses such types |
| * as __u64. |
| */ |
| #include "bpf_helper_defs.h" |
| |
| #define __uint(name, val) int (*name)[val] |
| #define __type(name, val) typeof(val) *name |
| #define __array(name, val) typeof(val) *name[] |
| #define __ulong(name, val) enum { ___bpf_concat(__unique_value, __COUNTER__) = val } name |
| |
| /* |
| * Helper macro to place programs, maps, license in |
| * different sections in elf_bpf file. Section names |
| * are interpreted by libbpf depending on the context (BPF programs, BPF maps, |
| * extern variables, etc). |
| * To allow use of SEC() with externs (e.g., for extern .maps declarations), |
| * make sure __attribute__((unused)) doesn't trigger compilation warning. |
| */ |
| #if __GNUC__ && !__clang__ |
| |
| /* |
| * Pragma macros are broken on GCC |
| * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55578 |
| * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90400 |
| */ |
| #define SEC(name) __attribute__((section(name), used)) |
| |
| #else |
| |
| #define SEC(name) \ |
| _Pragma("GCC diagnostic push") \ |
| _Pragma("GCC diagnostic ignored \"-Wignored-attributes\"") \ |
| __attribute__((section(name), used)) \ |
| _Pragma("GCC diagnostic pop") \ |
| |
| #endif |
| |
| /* Avoid 'linux/stddef.h' definition of '__always_inline'. */ |
| #undef __always_inline |
| #define __always_inline inline __attribute__((always_inline)) |
| |
| #ifndef __noinline |
| #define __noinline __attribute__((noinline)) |
| #endif |
| #ifndef __weak |
| #define __weak __attribute__((weak)) |
| #endif |
| |
| /* |
| * Use __hidden attribute to mark a non-static BPF subprogram effectively |
| * static for BPF verifier's verification algorithm purposes, allowing more |
| * extensive and permissive BPF verification process, taking into account |
| * subprogram's caller context. |
| */ |
| #define __hidden __attribute__((visibility("hidden"))) |
| |
| /* When utilizing vmlinux.h with BPF CO-RE, user BPF programs can't include |
| * any system-level headers (such as stddef.h, linux/version.h, etc), and |
| * commonly-used macros like NULL and KERNEL_VERSION aren't available through |
| * vmlinux.h. This just adds unnecessary hurdles and forces users to re-define |
| * them on their own. So as a convenience, provide such definitions here. |
| */ |
| #ifndef NULL |
| #define NULL ((void *)0) |
| #endif |
| |
| #ifndef KERNEL_VERSION |
| #define KERNEL_VERSION(a, b, c) (((a) << 16) + ((b) << 8) + ((c) > 255 ? 255 : (c))) |
| #endif |
| |
| /* |
| * Helper macros to manipulate data structures |
| */ |
| |
| /* offsetof() definition that uses __builtin_offset() might not preserve field |
| * offset CO-RE relocation properly, so force-redefine offsetof() using |
| * old-school approach which works with CO-RE correctly |
| */ |
| #undef offsetof |
| #define offsetof(type, member) ((unsigned long)&((type *)0)->member) |
| |
| /* redefined container_of() to ensure we use the above offsetof() macro */ |
| #undef container_of |
| #define container_of(ptr, type, member) \ |
| ({ \ |
| void *__mptr = (void *)(ptr); \ |
| ((type *)(__mptr - offsetof(type, member))); \ |
| }) |
| |
| /* |
| * Compiler (optimization) barrier. |
| */ |
| #ifndef barrier |
| #define barrier() asm volatile("" ::: "memory") |
| #endif |
| |
| /* Variable-specific compiler (optimization) barrier. It's a no-op which makes |
| * compiler believe that there is some black box modification of a given |
| * variable and thus prevents compiler from making extra assumption about its |
| * value and potential simplifications and optimizations on this variable. |
| * |
| * E.g., compiler might often delay or even omit 32-bit to 64-bit casting of |
| * a variable, making some code patterns unverifiable. Putting barrier_var() |
| * in place will ensure that cast is performed before the barrier_var() |
| * invocation, because compiler has to pessimistically assume that embedded |
| * asm section might perform some extra operations on that variable. |
| * |
| * This is a variable-specific variant of more global barrier(). |
| */ |
| #ifndef barrier_var |
| #define barrier_var(var) asm volatile("" : "+r"(var)) |
| #endif |
| |
| /* |
| * Helper macro to throw a compilation error if __bpf_unreachable() gets |
| * built into the resulting code. This works given BPF back end does not |
| * implement __builtin_trap(). This is useful to assert that certain paths |
| * of the program code are never used and hence eliminated by the compiler. |
| * |
| * For example, consider a switch statement that covers known cases used by |
| * the program. __bpf_unreachable() can then reside in the default case. If |
| * the program gets extended such that a case is not covered in the switch |
| * statement, then it will throw a build error due to the default case not |
| * being compiled out. |
| */ |
| #ifndef __bpf_unreachable |
| # define __bpf_unreachable() __builtin_trap() |
| #endif |
| |
| /* |
| * Helper function to perform a tail call with a constant/immediate map slot. |
| */ |
| #if (defined(__clang__) && __clang_major__ >= 8) || (!defined(__clang__) && __GNUC__ > 12) |
| #if defined(__bpf__) |
| static __always_inline void |
| bpf_tail_call_static(void *ctx, const void *map, const __u32 slot) |
| { |
| if (!__builtin_constant_p(slot)) |
| __bpf_unreachable(); |
| |
| /* |
| * Provide a hard guarantee that LLVM won't optimize setting r2 (map |
| * pointer) and r3 (constant map index) from _different paths_ ending |
| * up at the _same_ call insn as otherwise we won't be able to use the |
| * jmpq/nopl retpoline-free patching by the x86-64 JIT in the kernel |
| * given they mismatch. See also d2e4c1e6c294 ("bpf: Constant map key |
| * tracking for prog array pokes") for details on verifier tracking. |
| * |
| * Note on clobber list: we need to stay in-line with BPF calling |
| * convention, so even if we don't end up using r0, r4, r5, we need |
| * to mark them as clobber so that LLVM doesn't end up using them |
| * before / after the call. |
| */ |
| asm volatile("r1 = %[ctx]\n\t" |
| "r2 = %[map]\n\t" |
| "r3 = %[slot]\n\t" |
| "call 12" |
| :: [ctx]"r"(ctx), [map]"r"(map), [slot]"i"(slot) |
| : "r0", "r1", "r2", "r3", "r4", "r5"); |
| } |
| #endif |
| #endif |
| |
| enum libbpf_pin_type { |
| LIBBPF_PIN_NONE, |
| /* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */ |
| LIBBPF_PIN_BY_NAME, |
| }; |
| |
| enum libbpf_tristate { |
| TRI_NO = 0, |
| TRI_YES = 1, |
| TRI_MODULE = 2, |
| }; |
| |
| #define __kconfig __attribute__((section(".kconfig"))) |
| #define __ksym __attribute__((section(".ksyms"))) |
| #define __kptr_untrusted __attribute__((btf_type_tag("kptr_untrusted"))) |
| #define __kptr __attribute__((btf_type_tag("kptr"))) |
| #define __percpu_kptr __attribute__((btf_type_tag("percpu_kptr"))) |
| |
| #if defined (__clang__) |
| #define bpf_ksym_exists(sym) ({ \ |
| _Static_assert(!__builtin_constant_p(!!sym), \ |
| #sym " should be marked as __weak"); \ |
| !!sym; \ |
| }) |
| #elif __GNUC__ > 8 |
| #define bpf_ksym_exists(sym) ({ \ |
| _Static_assert(__builtin_has_attribute (*sym, __weak__), \ |
| #sym " should be marked as __weak"); \ |
| !!sym; \ |
| }) |
| #else |
| #define bpf_ksym_exists(sym) !!sym |
| #endif |
| |
| #define __arg_ctx __attribute__((btf_decl_tag("arg:ctx"))) |
| #define __arg_nonnull __attribute((btf_decl_tag("arg:nonnull"))) |
| #define __arg_nullable __attribute((btf_decl_tag("arg:nullable"))) |
| #define __arg_trusted __attribute((btf_decl_tag("arg:trusted"))) |
| #define __arg_arena __attribute((btf_decl_tag("arg:arena"))) |
| |
| #ifndef ___bpf_concat |
| #define ___bpf_concat(a, b) a ## b |
| #endif |
| #ifndef ___bpf_apply |
| #define ___bpf_apply(fn, n) ___bpf_concat(fn, n) |
| #endif |
| #ifndef ___bpf_nth |
| #define ___bpf_nth(_, _1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b, _c, N, ...) N |
| #endif |
| #ifndef ___bpf_narg |
| #define ___bpf_narg(...) \ |
| ___bpf_nth(_, ##__VA_ARGS__, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) |
| #endif |
| |
| #define ___bpf_fill0(arr, p, x) do {} while (0) |
| #define ___bpf_fill1(arr, p, x) arr[p] = x |
| #define ___bpf_fill2(arr, p, x, args...) arr[p] = x; ___bpf_fill1(arr, p + 1, args) |
| #define ___bpf_fill3(arr, p, x, args...) arr[p] = x; ___bpf_fill2(arr, p + 1, args) |
| #define ___bpf_fill4(arr, p, x, args...) arr[p] = x; ___bpf_fill3(arr, p + 1, args) |
| #define ___bpf_fill5(arr, p, x, args...) arr[p] = x; ___bpf_fill4(arr, p + 1, args) |
| #define ___bpf_fill6(arr, p, x, args...) arr[p] = x; ___bpf_fill5(arr, p + 1, args) |
| #define ___bpf_fill7(arr, p, x, args...) arr[p] = x; ___bpf_fill6(arr, p + 1, args) |
| #define ___bpf_fill8(arr, p, x, args...) arr[p] = x; ___bpf_fill7(arr, p + 1, args) |
| #define ___bpf_fill9(arr, p, x, args...) arr[p] = x; ___bpf_fill8(arr, p + 1, args) |
| #define ___bpf_fill10(arr, p, x, args...) arr[p] = x; ___bpf_fill9(arr, p + 1, args) |
| #define ___bpf_fill11(arr, p, x, args...) arr[p] = x; ___bpf_fill10(arr, p + 1, args) |
| #define ___bpf_fill12(arr, p, x, args...) arr[p] = x; ___bpf_fill11(arr, p + 1, args) |
| #define ___bpf_fill(arr, args...) \ |
| ___bpf_apply(___bpf_fill, ___bpf_narg(args))(arr, 0, args) |
| |
| /* |
| * BPF_SEQ_PRINTF to wrap bpf_seq_printf to-be-printed values |
| * in a structure. |
| */ |
| #define BPF_SEQ_PRINTF(seq, fmt, args...) \ |
| ({ \ |
| static const char ___fmt[] = fmt; \ |
| unsigned long long ___param[___bpf_narg(args)]; \ |
| \ |
| _Pragma("GCC diagnostic push") \ |
| _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \ |
| ___bpf_fill(___param, args); \ |
| _Pragma("GCC diagnostic pop") \ |
| \ |
| bpf_seq_printf(seq, ___fmt, sizeof(___fmt), \ |
| ___param, sizeof(___param)); \ |
| }) |
| |
| /* |
| * BPF_SNPRINTF wraps the bpf_snprintf helper with variadic arguments instead of |
| * an array of u64. |
| */ |
| #define BPF_SNPRINTF(out, out_size, fmt, args...) \ |
| ({ \ |
| static const char ___fmt[] = fmt; \ |
| unsigned long long ___param[___bpf_narg(args)]; \ |
| \ |
| _Pragma("GCC diagnostic push") \ |
| _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \ |
| ___bpf_fill(___param, args); \ |
| _Pragma("GCC diagnostic pop") \ |
| \ |
| bpf_snprintf(out, out_size, ___fmt, \ |
| ___param, sizeof(___param)); \ |
| }) |
| |
| #ifdef BPF_NO_GLOBAL_DATA |
| #define BPF_PRINTK_FMT_MOD |
| #else |
| #define BPF_PRINTK_FMT_MOD static const |
| #endif |
| |
| #define __bpf_printk(fmt, ...) \ |
| ({ \ |
| BPF_PRINTK_FMT_MOD char ____fmt[] = fmt; \ |
| bpf_trace_printk(____fmt, sizeof(____fmt), \ |
| ##__VA_ARGS__); \ |
| }) |
| |
| /* |
| * __bpf_vprintk wraps the bpf_trace_vprintk helper with variadic arguments |
| * instead of an array of u64. |
| */ |
| #define __bpf_vprintk(fmt, args...) \ |
| ({ \ |
| static const char ___fmt[] = fmt; \ |
| unsigned long long ___param[___bpf_narg(args)]; \ |
| \ |
| _Pragma("GCC diagnostic push") \ |
| _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \ |
| ___bpf_fill(___param, args); \ |
| _Pragma("GCC diagnostic pop") \ |
| \ |
| bpf_trace_vprintk(___fmt, sizeof(___fmt), \ |
| ___param, sizeof(___param)); \ |
| }) |
| |
| /* Use __bpf_printk when bpf_printk call has 3 or fewer fmt args |
| * Otherwise use __bpf_vprintk |
| */ |
| #define ___bpf_pick_printk(...) \ |
| ___bpf_nth(_, ##__VA_ARGS__, __bpf_vprintk, __bpf_vprintk, __bpf_vprintk, \ |
| __bpf_vprintk, __bpf_vprintk, __bpf_vprintk, __bpf_vprintk, \ |
| __bpf_vprintk, __bpf_vprintk, __bpf_printk /*3*/, __bpf_printk /*2*/,\ |
| __bpf_printk /*1*/, __bpf_printk /*0*/) |
| |
| /* Helper macro to print out debug messages */ |
| #define bpf_printk(fmt, args...) ___bpf_pick_printk(args)(fmt, ##args) |
| |
| struct bpf_iter_num; |
| |
| extern int bpf_iter_num_new(struct bpf_iter_num *it, int start, int end) __weak __ksym; |
| extern int *bpf_iter_num_next(struct bpf_iter_num *it) __weak __ksym; |
| extern void bpf_iter_num_destroy(struct bpf_iter_num *it) __weak __ksym; |
| |
| #ifndef bpf_for_each |
| /* bpf_for_each(iter_type, cur_elem, args...) provides generic construct for |
| * using BPF open-coded iterators without having to write mundane explicit |
| * low-level loop logic. Instead, it provides for()-like generic construct |
| * that can be used pretty naturally. E.g., for some hypothetical cgroup |
| * iterator, you'd write: |
| * |
| * struct cgroup *cg, *parent_cg = <...>; |
| * |
| * bpf_for_each(cgroup, cg, parent_cg, CG_ITER_CHILDREN) { |
| * bpf_printk("Child cgroup id = %d", cg->cgroup_id); |
| * if (cg->cgroup_id == 123) |
| * break; |
| * } |
| * |
| * I.e., it looks almost like high-level for each loop in other languages, |
| * supports continue/break, and is verifiable by BPF verifier. |
| * |
| * For iterating integers, the difference betwen bpf_for_each(num, i, N, M) |
| * and bpf_for(i, N, M) is in that bpf_for() provides additional proof to |
| * verifier that i is in [N, M) range, and in bpf_for_each() case i is `int |
| * *`, not just `int`. So for integers bpf_for() is more convenient. |
| * |
| * Note: this macro relies on C99 feature of allowing to declare variables |
| * inside for() loop, bound to for() loop lifetime. It also utilizes GCC |
| * extension: __attribute__((cleanup(<func>))), supported by both GCC and |
| * Clang. |
| */ |
| #define bpf_for_each(type, cur, args...) for ( \ |
| /* initialize and define destructor */ \ |
| struct bpf_iter_##type ___it __attribute__((aligned(8), /* enforce, just in case */, \ |
| cleanup(bpf_iter_##type##_destroy))), \ |
| /* ___p pointer is just to call bpf_iter_##type##_new() *once* to init ___it */ \ |
| *___p __attribute__((unused)) = ( \ |
| bpf_iter_##type##_new(&___it, ##args), \ |
| /* this is a workaround for Clang bug: it currently doesn't emit BTF */ \ |
| /* for bpf_iter_##type##_destroy() when used from cleanup() attribute */ \ |
| (void)bpf_iter_##type##_destroy, (void *)0); \ |
| /* iteration and termination check */ \ |
| (((cur) = bpf_iter_##type##_next(&___it))); \ |
| ) |
| #endif /* bpf_for_each */ |
| |
| #ifndef bpf_for |
| /* bpf_for(i, start, end) implements a for()-like looping construct that sets |
| * provided integer variable *i* to values starting from *start* through, |
| * but not including, *end*. It also proves to BPF verifier that *i* belongs |
| * to range [start, end), so this can be used for accessing arrays without |
| * extra checks. |
| * |
| * Note: *start* and *end* are assumed to be expressions with no side effects |
| * and whose values do not change throughout bpf_for() loop execution. They do |
| * not have to be statically known or constant, though. |
| * |
| * Note: similarly to bpf_for_each(), it relies on C99 feature of declaring for() |
| * loop bound variables and cleanup attribute, supported by GCC and Clang. |
| */ |
| #define bpf_for(i, start, end) for ( \ |
| /* initialize and define destructor */ \ |
| struct bpf_iter_num ___it __attribute__((aligned(8), /* enforce, just in case */ \ |
| cleanup(bpf_iter_num_destroy))), \ |
| /* ___p pointer is necessary to call bpf_iter_num_new() *once* to init ___it */ \ |
| *___p __attribute__((unused)) = ( \ |
| bpf_iter_num_new(&___it, (start), (end)), \ |
| /* this is a workaround for Clang bug: it currently doesn't emit BTF */ \ |
| /* for bpf_iter_num_destroy() when used from cleanup() attribute */ \ |
| (void)bpf_iter_num_destroy, (void *)0); \ |
| ({ \ |
| /* iteration step */ \ |
| int *___t = bpf_iter_num_next(&___it); \ |
| /* termination and bounds check */ \ |
| (___t && ((i) = *___t, (i) >= (start) && (i) < (end))); \ |
| }); \ |
| ) |
| #endif /* bpf_for */ |
| |
| #ifndef bpf_repeat |
| /* bpf_repeat(N) performs N iterations without exposing iteration number |
| * |
| * Note: similarly to bpf_for_each(), it relies on C99 feature of declaring for() |
| * loop bound variables and cleanup attribute, supported by GCC and Clang. |
| */ |
| #define bpf_repeat(N) for ( \ |
| /* initialize and define destructor */ \ |
| struct bpf_iter_num ___it __attribute__((aligned(8), /* enforce, just in case */ \ |
| cleanup(bpf_iter_num_destroy))), \ |
| /* ___p pointer is necessary to call bpf_iter_num_new() *once* to init ___it */ \ |
| *___p __attribute__((unused)) = ( \ |
| bpf_iter_num_new(&___it, 0, (N)), \ |
| /* this is a workaround for Clang bug: it currently doesn't emit BTF */ \ |
| /* for bpf_iter_num_destroy() when used from cleanup() attribute */ \ |
| (void)bpf_iter_num_destroy, (void *)0); \ |
| bpf_iter_num_next(&___it); \ |
| /* nothing here */ \ |
| ) |
| #endif /* bpf_repeat */ |
| |
| #endif |