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 | * | |
12 | * - attaches this program to eth0 raw socket | |
13 | * | |
14 | * - every second user space reads map[tcp], map[udp], map[icmp] to see | |
15 | * how many packets of given protocol were seen on eth0 | |
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> | |
29 | #include "libbpf.h" | |
9899694a | 30 | #include "sock_example.h" |
03f4723e | 31 | |
d40fc181 JS |
32 | char bpf_log_buf[BPF_LOG_BUF_SIZE]; |
33 | ||
03f4723e AS |
34 | static int test_sock(void) |
35 | { | |
36 | int sock = -1, map_fd, prog_fd, i, key; | |
37 | long long value = 0, tcp_cnt, udp_cnt, icmp_cnt; | |
38 | ||
39 | map_fd = bpf_create_map(BPF_MAP_TYPE_ARRAY, sizeof(key), sizeof(value), | |
89b97607 | 40 | 256, 0); |
03f4723e AS |
41 | if (map_fd < 0) { |
42 | printf("failed to create map '%s'\n", strerror(errno)); | |
43 | goto cleanup; | |
44 | } | |
45 | ||
46 | struct bpf_insn prog[] = { | |
47 | BPF_MOV64_REG(BPF_REG_6, BPF_REG_1), | |
48 | BPF_LD_ABS(BPF_B, ETH_HLEN + offsetof(struct iphdr, protocol) /* R0 = ip->proto */), | |
49 | BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -4), /* *(u32 *)(fp - 4) = r0 */ | |
50 | BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), | |
51 | BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), /* r2 = fp - 4 */ | |
52 | BPF_LD_MAP_FD(BPF_REG_1, map_fd), | |
53 | BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem), | |
54 | BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2), | |
55 | BPF_MOV64_IMM(BPF_REG_1, 1), /* r1 = 1 */ | |
56 | BPF_RAW_INSN(BPF_STX | BPF_XADD | BPF_DW, BPF_REG_0, BPF_REG_1, 0, 0), /* xadd r0 += r1 */ | |
57 | BPF_MOV64_IMM(BPF_REG_0, 0), /* r0 = 0 */ | |
58 | BPF_EXIT_INSN(), | |
59 | }; | |
43371c83 | 60 | size_t insns_cnt = sizeof(prog) / sizeof(struct bpf_insn); |
03f4723e | 61 | |
43371c83 | 62 | prog_fd = bpf_load_program(BPF_PROG_TYPE_SOCKET_FILTER, prog, insns_cnt, |
d40fc181 | 63 | "GPL", 0, bpf_log_buf, BPF_LOG_BUF_SIZE); |
03f4723e AS |
64 | if (prog_fd < 0) { |
65 | printf("failed to load prog '%s'\n", strerror(errno)); | |
66 | goto cleanup; | |
67 | } | |
68 | ||
69 | sock = open_raw_sock("lo"); | |
70 | ||
71 | if (setsockopt(sock, SOL_SOCKET, SO_ATTACH_BPF, &prog_fd, | |
72 | sizeof(prog_fd)) < 0) { | |
73 | printf("setsockopt %s\n", strerror(errno)); | |
74 | goto cleanup; | |
75 | } | |
76 | ||
77 | for (i = 0; i < 10; i++) { | |
78 | key = IPPROTO_TCP; | |
d40fc181 | 79 | assert(bpf_map_lookup_elem(map_fd, &key, &tcp_cnt) == 0); |
03f4723e AS |
80 | |
81 | key = IPPROTO_UDP; | |
d40fc181 | 82 | assert(bpf_map_lookup_elem(map_fd, &key, &udp_cnt) == 0); |
03f4723e AS |
83 | |
84 | key = IPPROTO_ICMP; | |
d40fc181 | 85 | assert(bpf_map_lookup_elem(map_fd, &key, &icmp_cnt) == 0); |
03f4723e AS |
86 | |
87 | printf("TCP %lld UDP %lld ICMP %lld packets\n", | |
88 | tcp_cnt, udp_cnt, icmp_cnt); | |
89 | sleep(1); | |
90 | } | |
91 | ||
92 | cleanup: | |
93 | /* maps, programs, raw sockets will auto cleanup on process exit */ | |
94 | return 0; | |
95 | } | |
96 | ||
97 | int main(void) | |
98 | { | |
99 | FILE *f; | |
100 | ||
101 | f = popen("ping -c5 localhost", "r"); | |
102 | (void)f; | |
103 | ||
104 | return test_sock(); | |
105 | } |