helpers.h

#include <linux/bpf.h>
#include <stdbool.h>
#include <stdint.h>

/* place things in different elf sections */
#define SEC(NAME) __attribute__((section(NAME), used))

/* helper functions */
static void* (*bpf_map_lookup_elem)(void* map, void* key) = (void*) BPF_FUNC_map_lookup_elem;
static int (*bpf_map_update_elem)(void* map, void* key, void* value,
                                  unsigned long long flags) = (void*) BPF_FUNC_map_update_elem;
static int (*bpf_map_delete_elem)(void* map, void* key) = (void*) BPF_FUNC_map_delete_elem;
static int (*bpf_probe_read)(void* dst, int size, void* unsafe_ptr) = (void*) BPF_FUNC_probe_read;
static unsigned long long (*bpf_ktime_get_ns)(void) = (void*) BPF_FUNC_ktime_get_ns;
static int (*bpf_trace_printk)(const char* fmt, int fmt_size, ...) = (void*) BPF_FUNC_trace_printk;
static unsigned long long (*bpf_get_current_pid_tgid)(void) = (void*) BPF_FUNC_get_current_pid_tgid;
static unsigned long long (*bpf_get_current_uid_gid)(void) = (void*) BPF_FUNC_get_current_uid_gid;
static unsigned long long (*bpf_get_smp_processor_id)(void) = (void*) BPF_FUNC_get_smp_processor_id;

/* loader usage */
struct bpf_map_def {
    unsigned int type;
    unsigned int key_size;
    unsigned int value_size;
    unsigned int max_entries;
    unsigned int map_flags;
    unsigned int pad1;
    unsigned int pad2;
};