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