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#include <linux/unistd.h>
#include <linux/bpf.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <unistd.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
#include "bpf_insn.h"
#include "sock_example.h"
#define BPF_F_PIN (1 << 0)
#define BPF_F_GET (1 << 1)
#define BPF_F_PIN_GET (BPF_F_PIN | BPF_F_GET)
#define BPF_F_KEY (1 << 2)
#define BPF_F_VAL (1 << 3)
#define BPF_F_KEY_VAL (BPF_F_KEY | BPF_F_VAL)
#define BPF_M_UNSPEC 0
#define BPF_M_MAP 1
#define BPF_M_PROG 2
char bpf_log_buf[BPF_LOG_BUF_SIZE];
static void usage(void)
{
printf("Usage: fds_example [...]\n");
printf(" -F <file> File to pin/get object\n");
printf(" -P |- pin object\n");
printf(" -G `- get object\n");
printf(" -m eBPF map mode\n");
printf(" -k <key> |- map key\n");
printf(" -v <value> `- map value\n");
printf(" -p eBPF prog mode\n");
printf(" -o <object> `- object file\n");
printf(" -h Display this help.\n");
}
static int bpf_prog_create(const char *object)
{
static struct bpf_insn insns[] = {
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
};
size_t insns_cnt = sizeof(insns) / sizeof(struct bpf_insn);
struct bpf_object *obj;
int err;
if (object) {
obj = bpf_object__open_file(object, NULL);
assert(!libbpf_get_error(obj));
err = bpf_object__load(obj);
assert(!err);
return bpf_program__fd(bpf_object__next_program(obj, NULL));
} else {
LIBBPF_OPTS(bpf_prog_load_opts, opts,
.log_buf = bpf_log_buf,
.log_size = BPF_LOG_BUF_SIZE,
);
return bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL",
insns, insns_cnt, &opts);
}
}
static int bpf_do_map(const char *file, uint32_t flags, uint32_t key,
uint32_t value)
{
int fd, ret;
if (flags & BPF_F_PIN) {
fd = bpf_map_create(BPF_MAP_TYPE_ARRAY, NULL, sizeof(uint32_t),
sizeof(uint32_t), 1024, NULL);
printf("bpf: map fd:%d (%s)\n", fd, strerror(errno));
assert(fd > 0);
ret = bpf_obj_pin(fd, file);
printf("bpf: pin ret:(%d,%s)\n", ret, strerror(errno));
assert(ret == 0);
} else {
fd = bpf_obj_get(file);
printf("bpf: get fd:%d (%s)\n", fd, strerror(errno));
assert(fd > 0);
}
if ((flags & BPF_F_KEY_VAL) == BPF_F_KEY_VAL) {
ret = bpf_map_update_elem(fd, &key, &value, 0);
printf("bpf: fd:%d u->(%u:%u) ret:(%d,%s)\n", fd, key, value,
ret, strerror(errno));
assert(ret == 0);
} else if (flags & BPF_F_KEY) {
ret = bpf_map_lookup_elem(fd, &key, &value);
printf("bpf: fd:%d l->(%u):%u ret:(%d,%s)\n", fd, key, value,
ret, strerror(errno));
assert(ret == 0);
}
return 0;
}
static int bpf_do_prog(const char *file, uint32_t flags, const char *object)
{
int fd, sock, ret;
if (flags & BPF_F_PIN) {
fd = bpf_prog_create(object);
printf("bpf: prog fd:%d (%s)\n", fd, strerror(errno));
assert(fd > 0);
ret = bpf_obj_pin(fd, file);
printf("bpf: pin ret:(%d,%s)\n", ret, strerror(errno));
assert(ret == 0);
} else {
fd = bpf_obj_get(file);
printf("bpf: get fd:%d (%s)\n", fd, strerror(errno));
assert(fd > 0);
}
sock = open_raw_sock("lo");
assert(sock > 0);
ret = setsockopt(sock, SOL_SOCKET, SO_ATTACH_BPF, &fd, sizeof(fd));
printf("bpf: sock:%d <- fd:%d attached ret:(%d,%s)\n", sock, fd,
ret, strerror(errno));
assert(ret == 0);
return 0;
}
int main(int argc, char **argv)
{
const char *file = NULL, *object = NULL;
uint32_t key = 0, value = 0, flags = 0;
int opt, mode = BPF_M_UNSPEC;
while ((opt = getopt(argc, argv, "F:PGmk:v:po:")) != -1) {
switch (opt) {
/* General args */
case 'F':
file = optarg;
break;
case 'P':
flags |= BPF_F_PIN;
break;
case 'G':
flags |= BPF_F_GET;
break;
/* Map-related args */
case 'm':
mode = BPF_M_MAP;
break;
case 'k':
key = strtoul(optarg, NULL, 0);
flags |= BPF_F_KEY;
break;
case 'v':
value = strtoul(optarg, NULL, 0);
flags |= BPF_F_VAL;
break;
/* Prog-related args */
case 'p':
mode = BPF_M_PROG;
break;
case 'o':
object = optarg;
break;
default:
goto out;
}
}
if (!(flags & BPF_F_PIN_GET) || !file)
goto out;
switch (mode) {
case BPF_M_MAP:
return bpf_do_map(file, flags, key, value);
case BPF_M_PROG:
return bpf_do_prog(file, flags, object);
}
out:
usage();
return -1;
}
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