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	0
31#define BPF_M_MAP	1
32#define BPF_M_PROG	2
33
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