projects/linux·blob master · refs

195 lines · 4.3 KiB

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}