samples/bpf/cookie_uid_helper_example.c - third_party/kernel - Git at Google

 /* This test is a demo of using get_socket_uid and get_socket_cookie
  * helper function to do per socket based network traffic monitoring.
  * It requires iptables version higher then 1.6.1. to load pinned eBPF
  * program into the xt_bpf match.
  *
  * TEST:
  * ./run_cookie_uid_helper_example.sh -option
  * option:
  *	-t: do traffic monitoring test, the program will continuously
  * print out network traffic happens after program started A sample
  * output is shown below:
  *
  * cookie: 877, uid: 0x3e8, Pakcet Count: 20, Bytes Count: 11058
  * cookie: 132, uid: 0x0, Pakcet Count: 2, Bytes Count: 286
  * cookie: 812, uid: 0x3e8, Pakcet Count: 3, Bytes Count: 1726
  * cookie: 802, uid: 0x3e8, Pakcet Count: 2, Bytes Count: 104
  * cookie: 877, uid: 0x3e8, Pakcet Count: 20, Bytes Count: 11058
  * cookie: 831, uid: 0x3e8, Pakcet Count: 2, Bytes Count: 104
  * cookie: 0, uid: 0x0, Pakcet Count: 6, Bytes Count: 712
  * cookie: 880, uid: 0xfffe, Pakcet Count: 1, Bytes Count: 70
  *
  *	-s: do getsockopt SO_COOKIE test, the program will set up a pair of
  * UDP sockets and send packets between them. And read out the traffic data
  * directly from the ebpf map based on the socket cookie.
  *
  * Clean up: if using shell script, the script file will delete the iptables
  * rule and unmount the bpf program when exit. Else the iptables rule need
  * to be deleted by hand, see run_cookie_uid_helper_example.sh for detail.
  */

 #define _GNU_SOURCE

 #define offsetof(type, member)	__builtin_offsetof(type, member)
 #define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))

 #include <arpa/inet.h>
 #include <errno.h>
 #include <error.h>
 #include <limits.h>
 #include <linux/bpf.h>
 #include <linux/if_ether.h>
 #include <net/if.h>
 #include <signal.h>
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
 #include <bpf/bpf.h>
 #include "bpf_insn.h"

 #define PORT 8888

 struct stats {
 	uint32_t uid;
 	uint64_t packets;
 	uint64_t bytes;
 };

 static int map_fd, prog_fd;

 static bool test_finish;

 static void maps_create(void)
 {
 	map_fd = bpf_map_create(BPF_MAP_TYPE_HASH, NULL, sizeof(uint32_t),
 				sizeof(struct stats), 100, NULL);
 	if (map_fd < 0)
 		error(1, errno, "map create failed!\n");
 }

 static void prog_load(void)
 {
 	static char log_buf[1 << 16];

 	struct bpf_insn prog[] = {
 		/*
 		 * Save sk_buff for future usage. value stored in R6 to R10 will
 		 * not be reset after a bpf helper function call.
 		 */
 		BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
 		/*
 		 * pc1: BPF_FUNC_get_socket_cookie takes one parameter,
 		 * R1: sk_buff
 		 */
 		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
 				BPF_FUNC_get_socket_cookie),
 		/* pc2-4: save &socketCookie to r7 for future usage*/
 		BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
 		BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
 		BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
 		/*
 		 * pc5-8: set up the registers for BPF_FUNC_map_lookup_elem,
 		 * it takes two parameters (R1: map_fd,  R2: &socket_cookie)
 		 */
 		BPF_LD_MAP_FD(BPF_REG_1, map_fd),
 		BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),
 		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
 				BPF_FUNC_map_lookup_elem),
 		/*
 		 * pc9. if r0 != 0x0, go to pc+14, since we have the cookie
 		 * stored already
 		 * Otherwise do pc10-22 to setup a new data entry.
 		 */
 		BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 14),
 		BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
 		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
 				BPF_FUNC_get_socket_uid),
 		/*
 		 * Place a struct stats in the R10 stack and sequentially
 		 * place the member value into the memory. Packets value
 		 * is set by directly place a IMM value 1 into the stack.
 		 */
 		BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0,
 			    -32 + (__s16)offsetof(struct stats, uid)),
 		BPF_ST_MEM(BPF_DW, BPF_REG_10,
 			   -32 + (__s16)offsetof(struct stats, packets), 1),
 		/*
 		 * __sk_buff is a special struct used for eBPF program to
 		 * directly access some sk_buff field.
 		 */
 		BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_6,
 				offsetof(struct __sk_buff, len)),
 		BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_1,
 			    -32 + (__s16)offsetof(struct stats, bytes)),
 		/*
 		 * add new map entry using BPF_FUNC_map_update_elem, it takes
 		 * 4 parameters (R1: map_fd, R2: &socket_cookie, R3: &stats,
 		 * R4: flags)
 		 */
 		BPF_LD_MAP_FD(BPF_REG_1, map_fd),
 		BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),
 		BPF_MOV64_REG(BPF_REG_3, BPF_REG_10),
 		BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, -32),
 		BPF_MOV64_IMM(BPF_REG_4, 0),
 		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
 				BPF_FUNC_map_update_elem),
 		BPF_JMP_IMM(BPF_JA, 0, 0, 5),
 		/*
 		 * pc24-30 update the packet info to a exist data entry, it can
 		 * be done by directly write to pointers instead of using
 		 * BPF_FUNC_map_update_elem helper function
 		 */
 		BPF_MOV64_REG(BPF_REG_9, BPF_REG_0),
 		BPF_MOV64_IMM(BPF_REG_1, 1),
 		BPF_ATOMIC_OP(BPF_DW, BPF_ADD, BPF_REG_9, BPF_REG_1,
 			      offsetof(struct stats, packets)),
 		BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_6,
 				offsetof(struct __sk_buff, len)),
 		BPF_ATOMIC_OP(BPF_DW, BPF_ADD, BPF_REG_9, BPF_REG_1,
 			      offsetof(struct stats, bytes)),
 		BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_6,
 				offsetof(struct __sk_buff, len)),
 		BPF_EXIT_INSN(),
 	};
 	LIBBPF_OPTS(bpf_prog_load_opts, opts,
 		.log_buf = log_buf,
 		.log_size = sizeof(log_buf),
 	);

 	prog_fd = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL",
 				prog, ARRAY_SIZE(prog), &opts);
 	if (prog_fd < 0)
 		error(1, errno, "failed to load prog\n%s\n", log_buf);
 }

 static void prog_attach_iptables(char *file)
 {
 	int ret;
 	char rules[256];

 	if (bpf_obj_pin(prog_fd, file))
 		error(1, errno, "bpf_obj_pin");
 	if (strlen(file) > 50) {
 		printf("file path too long: %s\n", file);
 		exit(1);
 	}
 	ret = snprintf(rules, sizeof(rules),
 		       "iptables -A OUTPUT -m bpf --object-pinned %s -j ACCEPT",
 		       file);
 	if (ret < 0 || ret >= sizeof(rules)) {
 		printf("error constructing iptables command\n");
 		exit(1);
 	}
 	ret = system(rules);
 	if (ret < 0) {
 		printf("iptables rule update failed: %d/n", WEXITSTATUS(ret));
 		exit(1);
 	}
 }

 static void print_table(void)
 {
 	struct stats curEntry;
 	uint32_t curN = UINT32_MAX;
 	uint32_t nextN;
 	int res;

 	while (bpf_map_get_next_key(map_fd, &curN, &nextN) > -1) {
 		curN = nextN;
 		res = bpf_map_lookup_elem(map_fd, &curN, &curEntry);
 		if (res < 0) {
 			error(1, errno, "fail to get entry value of Key: %u\n",
 				curN);
 		} else {
 			printf("cookie: %u, uid: 0x%x, Packet Count: %lu,"
 				" Bytes Count: %lu\n", curN, curEntry.uid,
 				curEntry.packets, curEntry.bytes);
 		}
 	}
 }

 static void udp_client(void)
 {
 	struct sockaddr_in si_other = {0};
 	struct sockaddr_in si_me = {0};
 	struct stats dataEntry;
 	int s_rcv, s_send, i, recv_len;
 	char message = 'a';
 	char buf;
 	uint64_t cookie;
 	int res;
 	socklen_t cookie_len = sizeof(cookie);
 	socklen_t slen = sizeof(si_other);

 	s_rcv = socket(PF_INET, SOCK_DGRAM, 0);
 	if (s_rcv < 0)
 		error(1, errno, "rcv socket creat failed!\n");
 	si_other.sin_family = AF_INET;
 	si_other.sin_port = htons(PORT);
 	if (inet_aton("127.0.0.1", &si_other.sin_addr) == 0)
 		error(1, errno, "inet_aton\n");
 	if (bind(s_rcv, (struct sockaddr *)&si_other, sizeof(si_other)) == -1)
 		error(1, errno, "bind\n");
 	s_send = socket(PF_INET, SOCK_DGRAM, 0);
 	if (s_send < 0)
 		error(1, errno, "send socket creat failed!\n");
 	res = getsockopt(s_send, SOL_SOCKET, SO_COOKIE, &cookie, &cookie_len);
 	if (res < 0)
 		printf("get cookie failed: %s\n", strerror(errno));
 	res = bpf_map_lookup_elem(map_fd, &cookie, &dataEntry);
 	if (res != -1)
 		error(1, errno, "socket stat found while flow not active\n");
 	for (i = 0; i < 10; i++) {
 		res = sendto(s_send, &message, sizeof(message), 0,
 			     (struct sockaddr *)&si_other, slen);
 		if (res == -1)
 			error(1, errno, "send\n");
 		if (res != sizeof(message))
 			error(1, 0, "%uB != %luB\n", res, sizeof(message));
 		recv_len = recvfrom(s_rcv, &buf, sizeof(buf), 0,
 			     (struct sockaddr *)&si_me, &slen);
 		if (recv_len < 0)
 			error(1, errno, "receive\n");
 		res = memcmp(&(si_other.sin_addr), &(si_me.sin_addr),
 			   sizeof(si_me.sin_addr));
 		if (res != 0)
 			error(1, EFAULT, "sender addr error: %d\n", res);
 		printf("Message received: %c\n", buf);
 		res = bpf_map_lookup_elem(map_fd, &cookie, &dataEntry);
 		if (res < 0)
 			error(1, errno, "lookup sk stat failed, cookie: %lu\n",
 			      cookie);
 		printf("cookie: %lu, uid: 0x%x, Packet Count: %lu,"
 			" Bytes Count: %lu\n\n", cookie, dataEntry.uid,
 			dataEntry.packets, dataEntry.bytes);
 	}
 	close(s_send);
 	close(s_rcv);
 }

 static int usage(void)
 {
 	printf("Usage: ./run_cookie_uid_helper_example.sh"
 		" bpfObjName -option\n"
 		"	-t	traffic monitor test\n"
 		"	-s	getsockopt cookie test\n");
 	return 1;
 }

 static void finish(int ret)
 {
 	test_finish = true;
 }

 int main(int argc, char *argv[])
 {
 	int opt;
 	bool cfg_test_traffic = false;
 	bool cfg_test_cookie = false;

 	if (argc != 3)
 		return usage();
 	while ((opt = getopt(argc, argv, "ts")) != -1) {
 		switch (opt) {
 		case 't':
 			cfg_test_traffic = true;
 			break;
 		case 's':
 			cfg_test_cookie = true;
 			break;

 		default:
 			printf("unknown option %c\n", opt);
 			usage();
 			return -1;
 		}
 	}
 	maps_create();
 	prog_load();
 	prog_attach_iptables(argv[2]);
 	if (cfg_test_traffic) {
 		if (signal(SIGINT, finish) == SIG_ERR)
 			error(1, errno, "register SIGINT handler failed");
 		if (signal(SIGTERM, finish) == SIG_ERR)
 			error(1, errno, "register SIGTERM handler failed");
 		while (!test_finish) {
 			print_table();
 			printf("\n");
 			sleep(1);
 		}
 	} else if (cfg_test_cookie) {
 		udp_client();
 	}
 	close(prog_fd);
 	close(map_fd);
 	return 0;
 }
	/* This test is a demo of using get_socket_uid and get_socket_cookie
	* helper function to do per socket based network traffic monitoring.
	* It requires iptables version higher then 1.6.1. to load pinned eBPF
	* program into the xt_bpf match.
	*
	* TEST:
	* ./run_cookie_uid_helper_example.sh -option
	* option:
	* -t: do traffic monitoring test, the program will continuously
	* print out network traffic happens after program started A sample
	* output is shown below:
	*
	* cookie: 877, uid: 0x3e8, Pakcet Count: 20, Bytes Count: 11058
	* cookie: 132, uid: 0x0, Pakcet Count: 2, Bytes Count: 286
	* cookie: 812, uid: 0x3e8, Pakcet Count: 3, Bytes Count: 1726
	* cookie: 802, uid: 0x3e8, Pakcet Count: 2, Bytes Count: 104
	* cookie: 877, uid: 0x3e8, Pakcet Count: 20, Bytes Count: 11058
	* cookie: 831, uid: 0x3e8, Pakcet Count: 2, Bytes Count: 104
	* cookie: 0, uid: 0x0, Pakcet Count: 6, Bytes Count: 712
	* cookie: 880, uid: 0xfffe, Pakcet Count: 1, Bytes Count: 70
	*
	* -s: do getsockopt SO_COOKIE test, the program will set up a pair of
	* UDP sockets and send packets between them. And read out the traffic data
	* directly from the ebpf map based on the socket cookie.
	*
	* Clean up: if using shell script, the script file will delete the iptables
	* rule and unmount the bpf program when exit. Else the iptables rule need
	* to be deleted by hand, see run_cookie_uid_helper_example.sh for detail.
	*/

	#define _GNU_SOURCE

	#define offsetof(type, member) __builtin_offsetof(type, member)
	#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))

	#include <arpa/inet.h>
	#include <errno.h>
	#include <error.h>
	#include <limits.h>
	#include <linux/bpf.h>
	#include <linux/if_ether.h>
	#include <net/if.h>
	#include <signal.h>
	#include <stdbool.h>
	#include <stdint.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <sys/socket.h>
	#include <sys/stat.h>
	#include <sys/types.h>
	#include <unistd.h>
	#include <bpf/bpf.h>
	#include "bpf_insn.h"

	#define PORT 8888

	struct stats {
	uint32_t uid;
	uint64_t packets;
	uint64_t bytes;
	};

	static int map_fd, prog_fd;

	static bool test_finish;

	static void maps_create(void)
	{
	map_fd = bpf_map_create(BPF_MAP_TYPE_HASH, NULL, sizeof(uint32_t),
	sizeof(struct stats), 100, NULL);
	if (map_fd < 0)
	error(1, errno, "map create failed!\n");
	}

	static void prog_load(void)
	{
	static char log_buf[1 << 16];

	struct bpf_insn prog[] = {
	/*
	* Save sk_buff for future usage. value stored in R6 to R10 will
	* not be reset after a bpf helper function call.
	*/
	BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
	/*
	* pc1: BPF_FUNC_get_socket_cookie takes one parameter,
	* R1: sk_buff
	*/
	BPF_RAW_INSN(BPF_JMP \| BPF_CALL, 0, 0, 0,
	BPF_FUNC_get_socket_cookie),
	/* pc2-4: save &socketCookie to r7 for future usage*/
	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
	BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
	BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
	/*
	* pc5-8: set up the registers for BPF_FUNC_map_lookup_elem,
	* it takes two parameters (R1: map_fd, R2: &socket_cookie)
	*/
	BPF_LD_MAP_FD(BPF_REG_1, map_fd),
	BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),
	BPF_RAW_INSN(BPF_JMP \| BPF_CALL, 0, 0, 0,
	BPF_FUNC_map_lookup_elem),
	/*
	* pc9. if r0 != 0x0, go to pc+14, since we have the cookie
	* stored already
	* Otherwise do pc10-22 to setup a new data entry.
	*/
	BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 14),
	BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
	BPF_RAW_INSN(BPF_JMP \| BPF_CALL, 0, 0, 0,
	BPF_FUNC_get_socket_uid),
	/*
	* Place a struct stats in the R10 stack and sequentially
	* place the member value into the memory. Packets value
	* is set by directly place a IMM value 1 into the stack.
	*/
	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0,
	-32 + (__s16)offsetof(struct stats, uid)),
	BPF_ST_MEM(BPF_DW, BPF_REG_10,
	-32 + (__s16)offsetof(struct stats, packets), 1),
	/*
	* __sk_buff is a special struct used for eBPF program to
	* directly access some sk_buff field.
	*/
	BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_6,
	offsetof(struct __sk_buff, len)),
	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_1,
	-32 + (__s16)offsetof(struct stats, bytes)),
	/*
	* add new map entry using BPF_FUNC_map_update_elem, it takes
	* 4 parameters (R1: map_fd, R2: &socket_cookie, R3: &stats,
	* R4: flags)
	*/
	BPF_LD_MAP_FD(BPF_REG_1, map_fd),
	BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),
	BPF_MOV64_REG(BPF_REG_3, BPF_REG_10),
	BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, -32),
	BPF_MOV64_IMM(BPF_REG_4, 0),
	BPF_RAW_INSN(BPF_JMP \| BPF_CALL, 0, 0, 0,
	BPF_FUNC_map_update_elem),
	BPF_JMP_IMM(BPF_JA, 0, 0, 5),
	/*
	* pc24-30 update the packet info to a exist data entry, it can
	* be done by directly write to pointers instead of using
	* BPF_FUNC_map_update_elem helper function
	*/
	BPF_MOV64_REG(BPF_REG_9, BPF_REG_0),
	BPF_MOV64_IMM(BPF_REG_1, 1),
	BPF_ATOMIC_OP(BPF_DW, BPF_ADD, BPF_REG_9, BPF_REG_1,
	offsetof(struct stats, packets)),
	BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_6,
	offsetof(struct __sk_buff, len)),
	BPF_ATOMIC_OP(BPF_DW, BPF_ADD, BPF_REG_9, BPF_REG_1,
	offsetof(struct stats, bytes)),
	BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_6,
	offsetof(struct __sk_buff, len)),
	BPF_EXIT_INSN(),
	};
	LIBBPF_OPTS(bpf_prog_load_opts, opts,
	.log_buf = log_buf,
	.log_size = sizeof(log_buf),
	);

	prog_fd = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL",
	prog, ARRAY_SIZE(prog), &opts);
	if (prog_fd < 0)
	error(1, errno, "failed to load prog\n%s\n", log_buf);
	}

	static void prog_attach_iptables(char *file)
	{
	int ret;
	char rules[256];

	if (bpf_obj_pin(prog_fd, file))
	error(1, errno, "bpf_obj_pin");
	if (strlen(file) > 50) {
	printf("file path too long: %s\n", file);
	exit(1);
	}
	ret = snprintf(rules, sizeof(rules),
	"iptables -A OUTPUT -m bpf --object-pinned %s -j ACCEPT",
	file);
	if (ret < 0 \|\| ret >= sizeof(rules)) {
	printf("error constructing iptables command\n");
	exit(1);
	}
	ret = system(rules);
	if (ret < 0) {
	printf("iptables rule update failed: %d/n", WEXITSTATUS(ret));
	exit(1);
	}
	}

	static void print_table(void)
	{
	struct stats curEntry;
	uint32_t curN = UINT32_MAX;
	uint32_t nextN;
	int res;

	while (bpf_map_get_next_key(map_fd, &curN, &nextN) > -1) {
	curN = nextN;
	res = bpf_map_lookup_elem(map_fd, &curN, &curEntry);
	if (res < 0) {
	error(1, errno, "fail to get entry value of Key: %u\n",
	curN);
	} else {
	printf("cookie: %u, uid: 0x%x, Packet Count: %lu,"
	" Bytes Count: %lu\n", curN, curEntry.uid,
	curEntry.packets, curEntry.bytes);
	}
	}
	}

	static void udp_client(void)
	{
	struct sockaddr_in si_other = {0};
	struct sockaddr_in si_me = {0};
	struct stats dataEntry;
	int s_rcv, s_send, i, recv_len;
	char message = 'a';
	char buf;
	uint64_t cookie;
	int res;
	socklen_t cookie_len = sizeof(cookie);
	socklen_t slen = sizeof(si_other);

	s_rcv = socket(PF_INET, SOCK_DGRAM, 0);
	if (s_rcv < 0)
	error(1, errno, "rcv socket creat failed!\n");
	si_other.sin_family = AF_INET;
	si_other.sin_port = htons(PORT);
	if (inet_aton("127.0.0.1", &si_other.sin_addr) == 0)
	error(1, errno, "inet_aton\n");
	if (bind(s_rcv, (struct sockaddr *)&si_other, sizeof(si_other)) == -1)
	error(1, errno, "bind\n");
	s_send = socket(PF_INET, SOCK_DGRAM, 0);
	if (s_send < 0)
	error(1, errno, "send socket creat failed!\n");
	res = getsockopt(s_send, SOL_SOCKET, SO_COOKIE, &cookie, &cookie_len);
	if (res < 0)
	printf("get cookie failed: %s\n", strerror(errno));
	res = bpf_map_lookup_elem(map_fd, &cookie, &dataEntry);
	if (res != -1)
	error(1, errno, "socket stat found while flow not active\n");
	for (i = 0; i < 10; i++) {
	res = sendto(s_send, &message, sizeof(message), 0,
	(struct sockaddr *)&si_other, slen);
	if (res == -1)
	error(1, errno, "send\n");
	if (res != sizeof(message))
	error(1, 0, "%uB != %luB\n", res, sizeof(message));
	recv_len = recvfrom(s_rcv, &buf, sizeof(buf), 0,
	(struct sockaddr *)&si_me, &slen);
	if (recv_len < 0)
	error(1, errno, "receive\n");
	res = memcmp(&(si_other.sin_addr), &(si_me.sin_addr),
	sizeof(si_me.sin_addr));
	if (res != 0)
	error(1, EFAULT, "sender addr error: %d\n", res);
	printf("Message received: %c\n", buf);
	res = bpf_map_lookup_elem(map_fd, &cookie, &dataEntry);
	if (res < 0)
	error(1, errno, "lookup sk stat failed, cookie: %lu\n",
	cookie);
	printf("cookie: %lu, uid: 0x%x, Packet Count: %lu,"
	" Bytes Count: %lu\n\n", cookie, dataEntry.uid,
	dataEntry.packets, dataEntry.bytes);
	}
	close(s_send);
	close(s_rcv);
	}

	static int usage(void)
	{
	printf("Usage: ./run_cookie_uid_helper_example.sh"
	" bpfObjName -option\n"
	" -t traffic monitor test\n"
	" -s getsockopt cookie test\n");
	return 1;
	}

	static void finish(int ret)
	{
	test_finish = true;
	}

	int main(int argc, char *argv[])
	{
	int opt;
	bool cfg_test_traffic = false;
	bool cfg_test_cookie = false;

	if (argc != 3)
	return usage();
	while ((opt = getopt(argc, argv, "ts")) != -1) {
	switch (opt) {
	case 't':
	cfg_test_traffic = true;
	break;
	case 's':
	cfg_test_cookie = true;
	break;

	default:
	printf("unknown option %c\n", opt);
	usage();
	return -1;
	}
	}
	maps_create();
	prog_load();
	prog_attach_iptables(argv[2]);
	if (cfg_test_traffic) {
	if (signal(SIGINT, finish) == SIG_ERR)
	error(1, errno, "register SIGINT handler failed");
	if (signal(SIGTERM, finish) == SIG_ERR)
	error(1, errno, "register SIGTERM handler failed");
	while (!test_finish) {
	print_table();
	printf("\n");
	sleep(1);
	}
	} else if (cfg_test_cookie) {
	udp_client();
	}
	close(prog_fd);
	close(map_fd);
	return 0;
	}