/* 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

#ifndef likely
#define likely(x)      (__builtin_expect(!!(x), 1))
#endif

#ifndef unlikely
#define unlikely(x)    (__builtin_expect(!!(x), 0))
#endif

/*
 * 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")))
#define __uptr __attribute__((btf_type_tag("uptr")))

#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_untrusted __attribute((btf_decl_tag("arg:untrusted")))
#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));          \
})

#define bpf_stream_printk(stream_id, 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_stream_vprintk(stream_id, ___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 between 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