/* 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;}