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
 21#define BPF_F_PIN	(1 << 0)
 22#define BPF_F_GET	(1 << 1)
 23#define BPF_F_PIN_GET	(BPF_F_PIN | BPF_F_GET)
 24
 25#define BPF_F_KEY	(1 << 2)
 26#define BPF_F_VAL	(1 << 3)
 27#define BPF_F_KEY_VAL	(BPF_F_KEY | BPF_F_VAL)
 28
 29#define BPF_M_UNSPEC	0
 30#define BPF_M_MAP	1
 31#define BPF_M_PROG	2
 32
 33char bpf_log_buf[BPF_LOG_BUF_SIZE];
 34
 35static void usage(void)
 36{
 37	printf("Usage: fds_example [...]\n");
 38	printf("       -F <file>   File to pin/get object\n");
 39	printf("       -P          |- pin object\n");
 40	printf("       -G          `- get object\n");
 41	printf("       -m          eBPF map mode\n");
 42	printf("       -k <key>    |- map key\n");
 43	printf("       -v <value>  `- map value\n");
 44	printf("       -p          eBPF prog mode\n");
 45	printf("       -o <object> `- object file\n");
 46	printf("       -h          Display this help.\n");
 47}
 48
 49static int bpf_map_create(void)
 50{
 51	return bpf_create_map(BPF_MAP_TYPE_ARRAY, sizeof(uint32_t),
 52			      sizeof(uint32_t), 1024, 0);
 53}
 54
 55static int bpf_prog_create(const char *object)
 56{
 57	static struct bpf_insn insns[] = {
 58		BPF_MOV64_IMM(BPF_REG_0, 1),
 59		BPF_EXIT_INSN(),
 60	};
 61	size_t insns_cnt = sizeof(insns) / sizeof(struct bpf_insn);
 62	struct bpf_object *obj;
 63	int prog_fd;
 64
 65	if (object) {
 66		assert(!bpf_prog_load(object, BPF_PROG_TYPE_UNSPEC,
 67				      &obj, &prog_fd));
 68		return prog_fd;
 69	} else {
 70		return bpf_load_program(BPF_PROG_TYPE_SOCKET_FILTER,
 71					insns, insns_cnt, "GPL", 0,
 72					bpf_log_buf, BPF_LOG_BUF_SIZE);
 73	}
 74}
 75
 76static int bpf_do_map(const char *file, uint32_t flags, uint32_t key,
 77		      uint32_t value)
 78{
 79	int fd, ret;
 80
 81	if (flags & BPF_F_PIN) {
 82		fd = bpf_map_create();
 83		printf("bpf: map fd:%d (%s)\n", fd, strerror(errno));
 84		assert(fd > 0);
 85
 86		ret = bpf_obj_pin(fd, file);
 87		printf("bpf: pin ret:(%d,%s)\n", ret, strerror(errno));
 88		assert(ret == 0);
 89	} else {
 90		fd = bpf_obj_get(file);
 91		printf("bpf: get fd:%d (%s)\n", fd, strerror(errno));
 92		assert(fd > 0);
 93	}
 94
 95	if ((flags & BPF_F_KEY_VAL) == BPF_F_KEY_VAL) {
 96		ret = bpf_map_update_elem(fd, &key, &value, 0);
 97		printf("bpf: fd:%d u->(%u:%u) ret:(%d,%s)\n", fd, key, value,
 98		       ret, strerror(errno));
 99		assert(ret == 0);
100	} else if (flags & BPF_F_KEY) {
101		ret = bpf_map_lookup_elem(fd, &key, &value);
102		printf("bpf: fd:%d l->(%u):%u ret:(%d,%s)\n", fd, key, value,
103		       ret, strerror(errno));
104		assert(ret == 0);
105	}
106
107	return 0;
108}
109
110static int bpf_do_prog(const char *file, uint32_t flags, const char *object)
111{
112	int fd, sock, ret;
113
114	if (flags & BPF_F_PIN) {
115		fd = bpf_prog_create(object);
116		printf("bpf: prog fd:%d (%s)\n", fd, strerror(errno));
117		assert(fd > 0);
118
119		ret = bpf_obj_pin(fd, file);
120		printf("bpf: pin ret:(%d,%s)\n", ret, strerror(errno));
121		assert(ret == 0);
122	} else {
123		fd = bpf_obj_get(file);
124		printf("bpf: get fd:%d (%s)\n", fd, strerror(errno));
125		assert(fd > 0);
126	}
127
128	sock = open_raw_sock("lo");
129	assert(sock > 0);
130
131	ret = setsockopt(sock, SOL_SOCKET, SO_ATTACH_BPF, &fd, sizeof(fd));
132	printf("bpf: sock:%d <- fd:%d attached ret:(%d,%s)\n", sock, fd,
133	       ret, strerror(errno));
134	assert(ret == 0);
135
136	return 0;
137}
138
139int main(int argc, char **argv)
140{
141	const char *file = NULL, *object = NULL;
142	uint32_t key = 0, value = 0, flags = 0;
143	int opt, mode = BPF_M_UNSPEC;
144
145	while ((opt = getopt(argc, argv, "F:PGmk:v:po:")) != -1) {
146		switch (opt) {
147		/* General args */
148		case 'F':
149			file = optarg;
150			break;
151		case 'P':
152			flags |= BPF_F_PIN;
153			break;
154		case 'G':
155			flags |= BPF_F_GET;
156			break;
157		/* Map-related args */
158		case 'm':
159			mode = BPF_M_MAP;
160			break;
161		case 'k':
162			key = strtoul(optarg, NULL, 0);
163			flags |= BPF_F_KEY;
164			break;
165		case 'v':
166			value = strtoul(optarg, NULL, 0);
167			flags |= BPF_F_VAL;
168			break;
169		/* Prog-related args */
170		case 'p':
171			mode = BPF_M_PROG;
172			break;
173		case 'o':
174			object = optarg;
175			break;
176		default:
177			goto out;
178		}
179	}
180
181	if (!(flags & BPF_F_PIN_GET) || !file)
182		goto out;
183
184	switch (mode) {
185	case BPF_M_MAP:
186		return bpf_do_map(file, flags, key, value);
187	case BPF_M_PROG:
188		return bpf_do_prog(file, flags, object);
189	}
190out:
191	usage();
192	return -1;
193}