[linux-2.6-block.git] / samples / bpf / sock_example.c

/* eBPF example program:
 * - creates arraymap in kernel with key 4 bytes and value 8 bytes
 *
 * - loads eBPF program:
 *   r0 = skb->data[ETH_HLEN + offsetof(struct iphdr, protocol)];
 *   *(u32*)(fp - 4) = r0;
 *   // assuming packet is IPv4, lookup ip->proto in a map
 *   value = bpf_map_lookup_elem(map_fd, fp - 4);
 *   if (value)
 *        (*(u64*)value) += 1;
 *
 * - attaches this program to loopback interface "lo" raw socket
 *
 * - every second user space reads map[tcp], map[udp], map[icmp] to see
 *   how many packets of given protocol were seen on "lo"
 */
#include <stdio.h>
#include <unistd.h>
#include <assert.h>
#include <linux/bpf.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <linux/if_ether.h>
#include <linux/ip.h>
#include <stddef.h>
#include <bpf/bpf.h>
#include "bpf_insn.h"
#include "sock_example.h"

char bpf_log_buf[BPF_LOG_BUF_SIZE];

static int test_sock(void)
{
	int sock = -1, map_fd, prog_fd, i, key;
	long long value = 0, tcp_cnt, udp_cnt, icmp_cnt;

	map_fd = bpf_create_map(BPF_MAP_TYPE_ARRAY, sizeof(key), sizeof(value),
				256, 0);
	if (map_fd < 0) {
		printf("failed to create map '%s'\n", strerror(errno));
		goto cleanup;
	}

	struct bpf_insn prog[] = {
		BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
		BPF_LD_ABS(BPF_B, ETH_HLEN + offsetof(struct iphdr, protocol) /* R0 = ip->proto */),
		BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -4), /* *(u32 *)(fp - 4) = r0 */
		BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
		BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), /* r2 = fp - 4 */
		BPF_LD_MAP_FD(BPF_REG_1, map_fd),
		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
		BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
		BPF_MOV64_IMM(BPF_REG_1, 1), /* r1 = 1 */
		BPF_RAW_INSN(BPF_STX | BPF_XADD | BPF_DW, BPF_REG_0, BPF_REG_1, 0, 0), /* xadd r0 += r1 */
		BPF_MOV64_IMM(BPF_REG_0, 0), /* r0 = 0 */
		BPF_EXIT_INSN(),
	};
	size_t insns_cnt = sizeof(prog) / sizeof(struct bpf_insn);

	prog_fd = bpf_load_program(BPF_PROG_TYPE_SOCKET_FILTER, prog, insns_cnt,
				   "GPL", 0, bpf_log_buf, BPF_LOG_BUF_SIZE);
	if (prog_fd < 0) {
		printf("failed to load prog '%s'\n", strerror(errno));
		goto cleanup;
	}

	sock = open_raw_sock("lo");

	if (setsockopt(sock, SOL_SOCKET, SO_ATTACH_BPF, &prog_fd,
		       sizeof(prog_fd)) < 0) {
		printf("setsockopt %s\n", strerror(errno));
		goto cleanup;
	}

	for (i = 0; i < 10; i++) {
		key = IPPROTO_TCP;
		assert(bpf_map_lookup_elem(map_fd, &key, &tcp_cnt) == 0);

		key = IPPROTO_UDP;
		assert(bpf_map_lookup_elem(map_fd, &key, &udp_cnt) == 0);

		key = IPPROTO_ICMP;
		assert(bpf_map_lookup_elem(map_fd, &key, &icmp_cnt) == 0);

		printf("TCP %lld UDP %lld ICMP %lld packets\n",
		       tcp_cnt, udp_cnt, icmp_cnt);
		sleep(1);
	}

cleanup:
	/* maps, programs, raw sockets will auto cleanup on process exit */
	return 0;
}

int main(void)
{
	FILE *f;

	f = popen("ping -4 -c5 localhost", "r");
	(void)f;

	return test_sock();
}
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	*
03f4723e AS	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>
8d930450 JK	30	#include "bpf_insn.h"
9899694a	31	#include "sock_example.h"
03f4723e	32
d40fc181 JS	33	char bpf_log_buf[BPF_LOG_BUF_SIZE];
d40fc181 JS	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
	40	map_fd = bpf_create_map(BPF_MAP_TYPE_ARRAY, sizeof(key), sizeof(value),
89b97607	41	256, 0);
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 */
	57	BPF_RAW_INSN(BPF_STX \| BPF_XADD \| BPF_DW, BPF_REG_0, BPF_REG_1, 0, 0), /* xadd r0 += r1 */
	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);
03f4723e	62
43371c83	63	prog_fd = bpf_load_program(BPF_PROG_TYPE_SOCKET_FILTER, prog, insns_cnt,
d40fc181	64	"GPL", 0, bpf_log_buf, BPF_LOG_BUF_SIZE);
03f4723e AS	65	if (prog_fd < 0) {
	66	printf("failed to load prog '%s'\n", strerror(errno));
	67	goto cleanup;
	68	}
	69
	70	sock = open_raw_sock("lo");
	71
	72	if (setsockopt(sock, SOL_SOCKET, SO_ATTACH_BPF, &prog_fd,
	73	sizeof(prog_fd)) < 0) {
	74	printf("setsockopt %s\n", strerror(errno));
	75	goto cleanup;
	76	}
	77
	78	for (i = 0; i < 10; i++) {
	79	key = IPPROTO_TCP;
d40fc181	80	assert(bpf_map_lookup_elem(map_fd, &key, &tcp_cnt) == 0);
03f4723e AS	81
03f4723e AS	82	key = IPPROTO_UDP;
d40fc181	83	assert(bpf_map_lookup_elem(map_fd, &key, &udp_cnt) == 0);
03f4723e AS	84
03f4723e AS	85	key = IPPROTO_ICMP;
d40fc181	86	assert(bpf_map_lookup_elem(map_fd, &key, &icmp_cnt) == 0);
03f4723e AS	87
	88	printf("TCP %lld UDP %lld ICMP %lld packets\n",
	89	tcp_cnt, udp_cnt, icmp_cnt);
	90	sleep(1);
	91	}
	92
	93	cleanup:
	94	/* maps, programs, raw sockets will auto cleanup on process exit */
	95	return 0;
	96	}
	97
	98	int main(void)
	99	{
	100	FILE *f;
	101
5c3cf87d	102	f = popen("ping -4 -c5 localhost", "r");
03f4723e AS	103	(void)f;
	104
	105	return test_sock();
	106	}