Commit | Line | Data |
---|---|---|
03f4723e AS |
1 | /* eBPF example program: |
2 | * - creates arraymap in kernel with key 4 bytes and value 8 bytes | |
3 | * | |
4 | * - loads eBPF program: | |
5 | * r0 = skb->data[ETH_HLEN + offsetof(struct iphdr, protocol)]; | |
6 | * *(u32*)(fp - 4) = r0; | |
7 | * // assuming packet is IPv4, lookup ip->proto in a map | |
8 | * value = bpf_map_lookup_elem(map_fd, fp - 4); | |
9 | * if (value) | |
10 | * (*(u64*)value) += 1; | |
11 | * | |
97c33610 | 12 | * - attaches this program to loopback interface "lo" raw socket |
03f4723e AS |
13 | * |
14 | * - every second user space reads map[tcp], map[udp], map[icmp] to see | |
97c33610 | 15 | * how many packets of given protocol were seen on "lo" |
03f4723e AS |
16 | */ |
17 | #include <stdio.h> | |
18 | #include <unistd.h> | |
19 | #include <assert.h> | |
20 | #include <linux/bpf.h> | |
21 | #include <string.h> | |
22 | #include <stdlib.h> | |
23 | #include <errno.h> | |
24 | #include <sys/socket.h> | |
25 | #include <arpa/inet.h> | |
26 | #include <linux/if_ether.h> | |
27 | #include <linux/ip.h> | |
28 | #include <stddef.h> | |
8d930450 JK |
29 | #include <bpf/bpf.h> |
30 | #include "bpf_insn.h" | |
9899694a | 31 | #include "sock_example.h" |
03f4723e | 32 | |
d40fc181 JS |
33 | char bpf_log_buf[BPF_LOG_BUF_SIZE]; |
34 | ||
03f4723e AS |
35 | static int test_sock(void) |
36 | { | |
37 | int sock = -1, map_fd, prog_fd, i, key; | |
38 | long long value = 0, tcp_cnt, udp_cnt, icmp_cnt; | |
39 | ||
c58f9815 AN |
40 | map_fd = bpf_map_create(BPF_MAP_TYPE_ARRAY, NULL, sizeof(key), sizeof(value), |
41 | 256, NULL); | |
03f4723e AS |
42 | if (map_fd < 0) { |
43 | printf("failed to create map '%s'\n", strerror(errno)); | |
44 | goto cleanup; | |
45 | } | |
46 | ||
47 | struct bpf_insn prog[] = { | |
48 | BPF_MOV64_REG(BPF_REG_6, BPF_REG_1), | |
49 | BPF_LD_ABS(BPF_B, ETH_HLEN + offsetof(struct iphdr, protocol) /* R0 = ip->proto */), | |
50 | BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -4), /* *(u32 *)(fp - 4) = r0 */ | |
51 | BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), | |
52 | BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), /* r2 = fp - 4 */ | |
53 | BPF_LD_MAP_FD(BPF_REG_1, map_fd), | |
54 | BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem), | |
55 | BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2), | |
56 | BPF_MOV64_IMM(BPF_REG_1, 1), /* r1 = 1 */ | |
91c960b0 | 57 | BPF_ATOMIC_OP(BPF_DW, BPF_ADD, BPF_REG_0, BPF_REG_1, 0), |
03f4723e AS |
58 | BPF_MOV64_IMM(BPF_REG_0, 0), /* r0 = 0 */ |
59 | BPF_EXIT_INSN(), | |
60 | }; | |
43371c83 | 61 | size_t insns_cnt = sizeof(prog) / sizeof(struct bpf_insn); |
c58f9815 AN |
62 | LIBBPF_OPTS(bpf_prog_load_opts, opts, |
63 | .log_buf = bpf_log_buf, | |
64 | .log_size = BPF_LOG_BUF_SIZE, | |
65 | ); | |
03f4723e | 66 | |
c58f9815 AN |
67 | prog_fd = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL", |
68 | prog, insns_cnt, &opts); | |
03f4723e AS |
69 | if (prog_fd < 0) { |
70 | printf("failed to load prog '%s'\n", strerror(errno)); | |
71 | goto cleanup; | |
72 | } | |
73 | ||
74 | sock = open_raw_sock("lo"); | |
75 | ||
76 | if (setsockopt(sock, SOL_SOCKET, SO_ATTACH_BPF, &prog_fd, | |
77 | sizeof(prog_fd)) < 0) { | |
78 | printf("setsockopt %s\n", strerror(errno)); | |
79 | goto cleanup; | |
80 | } | |
81 | ||
82 | for (i = 0; i < 10; i++) { | |
83 | key = IPPROTO_TCP; | |
d40fc181 | 84 | assert(bpf_map_lookup_elem(map_fd, &key, &tcp_cnt) == 0); |
03f4723e AS |
85 | |
86 | key = IPPROTO_UDP; | |
d40fc181 | 87 | assert(bpf_map_lookup_elem(map_fd, &key, &udp_cnt) == 0); |
03f4723e AS |
88 | |
89 | key = IPPROTO_ICMP; | |
d40fc181 | 90 | assert(bpf_map_lookup_elem(map_fd, &key, &icmp_cnt) == 0); |
03f4723e AS |
91 | |
92 | printf("TCP %lld UDP %lld ICMP %lld packets\n", | |
93 | tcp_cnt, udp_cnt, icmp_cnt); | |
94 | sleep(1); | |
95 | } | |
96 | ||
97 | cleanup: | |
98 | /* maps, programs, raw sockets will auto cleanup on process exit */ | |
99 | return 0; | |
100 | } | |
101 | ||
102 | int main(void) | |
103 | { | |
104 | FILE *f; | |
105 | ||
5c3cf87d | 106 | f = popen("ping -4 -c5 localhost", "r"); |
03f4723e AS |
107 | (void)f; |
108 | ||
109 | return test_sock(); | |
110 | } |