196 lines · c
1#include <linux/unistd.h>2#include <linux/bpf.h>3 4#include <stdio.h>5#include <stdlib.h>6#include <stdint.h>7#include <unistd.h>8#include <string.h>9#include <assert.h>10#include <errno.h>11 12#include <sys/types.h>13#include <sys/socket.h>14 15#include <bpf/bpf.h>16 17#include <bpf/libbpf.h>18#include "bpf_insn.h"19#include "sock_example.h"20#include "bpf_util.h"21 22#define BPF_F_PIN (1 << 0)23#define BPF_F_GET (1 << 1)24#define BPF_F_PIN_GET (BPF_F_PIN | BPF_F_GET)25 26#define BPF_F_KEY (1 << 2)27#define BPF_F_VAL (1 << 3)28#define BPF_F_KEY_VAL (BPF_F_KEY | BPF_F_VAL)29 30#define BPF_M_UNSPEC 031#define BPF_M_MAP 132#define BPF_M_PROG 233 34char bpf_log_buf[BPF_LOG_BUF_SIZE];35 36static void usage(void)37{38 printf("Usage: fds_example [...]\n");39 printf(" -F <file> File to pin/get object\n");40 printf(" -P |- pin object\n");41 printf(" -G `- get object\n");42 printf(" -m eBPF map mode\n");43 printf(" -k <key> |- map key\n");44 printf(" -v <value> `- map value\n");45 printf(" -p eBPF prog mode\n");46 printf(" -o <object> `- object file\n");47 printf(" -h Display this help.\n");48}49 50static int bpf_prog_create(const char *object)51{52 static struct bpf_insn insns[] = {53 BPF_MOV64_IMM(BPF_REG_0, 1),54 BPF_EXIT_INSN(),55 };56 size_t insns_cnt = ARRAY_SIZE(insns);57 struct bpf_object *obj;58 int err;59 60 if (object) {61 obj = bpf_object__open_file(object, NULL);62 assert(!libbpf_get_error(obj));63 err = bpf_object__load(obj);64 assert(!err);65 return bpf_program__fd(bpf_object__next_program(obj, NULL));66 } else {67 LIBBPF_OPTS(bpf_prog_load_opts, opts,68 .log_buf = bpf_log_buf,69 .log_size = BPF_LOG_BUF_SIZE,70 );71 72 return bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL",73 insns, insns_cnt, &opts);74 }75}76 77static int bpf_do_map(const char *file, uint32_t flags, uint32_t key,78 uint32_t value)79{80 int fd, ret;81 82 if (flags & BPF_F_PIN) {83 fd = bpf_map_create(BPF_MAP_TYPE_ARRAY, NULL, sizeof(uint32_t),84 sizeof(uint32_t), 1024, NULL);85 printf("bpf: map fd:%d (%s)\n", fd, strerror(errno));86 assert(fd > 0);87 88 ret = bpf_obj_pin(fd, file);89 printf("bpf: pin ret:(%d,%s)\n", ret, strerror(errno));90 assert(ret == 0);91 } else {92 fd = bpf_obj_get(file);93 printf("bpf: get fd:%d (%s)\n", fd, strerror(errno));94 assert(fd > 0);95 }96 97 if ((flags & BPF_F_KEY_VAL) == BPF_F_KEY_VAL) {98 ret = bpf_map_update_elem(fd, &key, &value, 0);99 printf("bpf: fd:%d u->(%u:%u) ret:(%d,%s)\n", fd, key, value,100 ret, strerror(errno));101 assert(ret == 0);102 } else if (flags & BPF_F_KEY) {103 ret = bpf_map_lookup_elem(fd, &key, &value);104 printf("bpf: fd:%d l->(%u):%u ret:(%d,%s)\n", fd, key, value,105 ret, strerror(errno));106 assert(ret == 0);107 }108 109 return 0;110}111 112static int bpf_do_prog(const char *file, uint32_t flags, const char *object)113{114 int fd, sock, ret;115 116 if (flags & BPF_F_PIN) {117 fd = bpf_prog_create(object);118 printf("bpf: prog fd:%d (%s)\n", fd, strerror(errno));119 assert(fd > 0);120 121 ret = bpf_obj_pin(fd, file);122 printf("bpf: pin ret:(%d,%s)\n", ret, strerror(errno));123 assert(ret == 0);124 } else {125 fd = bpf_obj_get(file);126 printf("bpf: get fd:%d (%s)\n", fd, strerror(errno));127 assert(fd > 0);128 }129 130 sock = open_raw_sock("lo");131 assert(sock > 0);132 133 ret = setsockopt(sock, SOL_SOCKET, SO_ATTACH_BPF, &fd, sizeof(fd));134 printf("bpf: sock:%d <- fd:%d attached ret:(%d,%s)\n", sock, fd,135 ret, strerror(errno));136 assert(ret == 0);137 138 return 0;139}140 141int main(int argc, char **argv)142{143 const char *file = NULL, *object = NULL;144 uint32_t key = 0, value = 0, flags = 0;145 int opt, mode = BPF_M_UNSPEC;146 147 while ((opt = getopt(argc, argv, "F:PGmk:v:po:")) != -1) {148 switch (opt) {149 /* General args */150 case 'F':151 file = optarg;152 break;153 case 'P':154 flags |= BPF_F_PIN;155 break;156 case 'G':157 flags |= BPF_F_GET;158 break;159 /* Map-related args */160 case 'm':161 mode = BPF_M_MAP;162 break;163 case 'k':164 key = strtoul(optarg, NULL, 0);165 flags |= BPF_F_KEY;166 break;167 case 'v':168 value = strtoul(optarg, NULL, 0);169 flags |= BPF_F_VAL;170 break;171 /* Prog-related args */172 case 'p':173 mode = BPF_M_PROG;174 break;175 case 'o':176 object = optarg;177 break;178 default:179 goto out;180 }181 }182 183 if (!(flags & BPF_F_PIN_GET) || !file)184 goto out;185 186 switch (mode) {187 case BPF_M_MAP:188 return bpf_do_map(file, flags, key, value);189 case BPF_M_PROG:190 return bpf_do_prog(file, flags, object);191 }192out:193 usage();194 return -1;195}196