333 lines · c
1/* This test is a demo of using get_socket_uid and get_socket_cookie2 * helper function to do per socket based network traffic monitoring.3 * It requires iptables version higher then 1.6.1. to load pinned eBPF4 * program into the xt_bpf match.5 *6 * TEST:7 * ./run_cookie_uid_helper_example.sh -option8 * option:9 * -t: do traffic monitoring test, the program will continuously10 * print out network traffic happens after program started A sample11 * output is shown below:12 *13 * cookie: 877, uid: 0x3e8, Pakcet Count: 20, Bytes Count: 1105814 * cookie: 132, uid: 0x0, Pakcet Count: 2, Bytes Count: 28615 * cookie: 812, uid: 0x3e8, Pakcet Count: 3, Bytes Count: 172616 * cookie: 802, uid: 0x3e8, Pakcet Count: 2, Bytes Count: 10417 * cookie: 877, uid: 0x3e8, Pakcet Count: 20, Bytes Count: 1105818 * cookie: 831, uid: 0x3e8, Pakcet Count: 2, Bytes Count: 10419 * cookie: 0, uid: 0x0, Pakcet Count: 6, Bytes Count: 71220 * cookie: 880, uid: 0xfffe, Pakcet Count: 1, Bytes Count: 7021 *22 * -s: do getsockopt SO_COOKIE test, the program will set up a pair of23 * UDP sockets and send packets between them. And read out the traffic data24 * directly from the ebpf map based on the socket cookie.25 *26 * Clean up: if using shell script, the script file will delete the iptables27 * rule and unmount the bpf program when exit. Else the iptables rule need28 * to be deleted by hand, see run_cookie_uid_helper_example.sh for detail.29 */30 31#define _GNU_SOURCE32 33#define offsetof(type, member) __builtin_offsetof(type, member)34#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))35 36#include <arpa/inet.h>37#include <errno.h>38#include <error.h>39#include <limits.h>40#include <linux/bpf.h>41#include <linux/if_ether.h>42#include <net/if.h>43#include <signal.h>44#include <stdbool.h>45#include <stdint.h>46#include <stdio.h>47#include <stdlib.h>48#include <string.h>49#include <sys/socket.h>50#include <sys/stat.h>51#include <sys/types.h>52#include <unistd.h>53#include <bpf/bpf.h>54#include "bpf_insn.h"55 56#define PORT 888857 58struct stats {59 uint32_t uid;60 uint64_t packets;61 uint64_t bytes;62};63 64static int map_fd, prog_fd;65 66static bool test_finish;67 68static void maps_create(void)69{70 map_fd = bpf_map_create(BPF_MAP_TYPE_HASH, NULL, sizeof(uint32_t),71 sizeof(struct stats), 100, NULL);72 if (map_fd < 0)73 error(1, errno, "map create failed!\n");74}75 76static void prog_load(void)77{78 static char log_buf[1 << 16];79 80 struct bpf_insn prog[] = {81 /*82 * Save sk_buff for future usage. value stored in R6 to R10 will83 * not be reset after a bpf helper function call.84 */85 BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),86 /*87 * pc1: BPF_FUNC_get_socket_cookie takes one parameter,88 * R1: sk_buff89 */90 BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,91 BPF_FUNC_get_socket_cookie),92 /* pc2-4: save &socketCookie to r7 for future usage*/93 BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),94 BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),95 BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),96 /*97 * pc5-8: set up the registers for BPF_FUNC_map_lookup_elem,98 * it takes two parameters (R1: map_fd, R2: &socket_cookie)99 */100 BPF_LD_MAP_FD(BPF_REG_1, map_fd),101 BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),102 BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,103 BPF_FUNC_map_lookup_elem),104 /*105 * pc9. if r0 != 0x0, go to pc+14, since we have the cookie106 * stored already107 * Otherwise do pc10-22 to setup a new data entry.108 */109 BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 14),110 BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),111 BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,112 BPF_FUNC_get_socket_uid),113 /*114 * Place a struct stats in the R10 stack and sequentially115 * place the member value into the memory. Packets value116 * is set by directly place a IMM value 1 into the stack.117 */118 BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0,119 -32 + (__s16)offsetof(struct stats, uid)),120 BPF_ST_MEM(BPF_DW, BPF_REG_10,121 -32 + (__s16)offsetof(struct stats, packets), 1),122 /*123 * __sk_buff is a special struct used for eBPF program to124 * directly access some sk_buff field.125 */126 BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_6,127 offsetof(struct __sk_buff, len)),128 BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_1,129 -32 + (__s16)offsetof(struct stats, bytes)),130 /*131 * add new map entry using BPF_FUNC_map_update_elem, it takes132 * 4 parameters (R1: map_fd, R2: &socket_cookie, R3: &stats,133 * R4: flags)134 */135 BPF_LD_MAP_FD(BPF_REG_1, map_fd),136 BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),137 BPF_MOV64_REG(BPF_REG_3, BPF_REG_10),138 BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, -32),139 BPF_MOV64_IMM(BPF_REG_4, 0),140 BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,141 BPF_FUNC_map_update_elem),142 BPF_JMP_IMM(BPF_JA, 0, 0, 5),143 /*144 * pc24-30 update the packet info to a exist data entry, it can145 * be done by directly write to pointers instead of using146 * BPF_FUNC_map_update_elem helper function147 */148 BPF_MOV64_REG(BPF_REG_9, BPF_REG_0),149 BPF_MOV64_IMM(BPF_REG_1, 1),150 BPF_ATOMIC_OP(BPF_DW, BPF_ADD, BPF_REG_9, BPF_REG_1,151 offsetof(struct stats, packets)),152 BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_6,153 offsetof(struct __sk_buff, len)),154 BPF_ATOMIC_OP(BPF_DW, BPF_ADD, BPF_REG_9, BPF_REG_1,155 offsetof(struct stats, bytes)),156 BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_6,157 offsetof(struct __sk_buff, len)),158 BPF_EXIT_INSN(),159 };160 LIBBPF_OPTS(bpf_prog_load_opts, opts,161 .log_buf = log_buf,162 .log_size = sizeof(log_buf),163 );164 165 prog_fd = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL",166 prog, ARRAY_SIZE(prog), &opts);167 if (prog_fd < 0)168 error(1, errno, "failed to load prog\n%s\n", log_buf);169}170 171static void prog_attach_iptables(char *file)172{173 int ret;174 char rules[256];175 176 if (bpf_obj_pin(prog_fd, file))177 error(1, errno, "bpf_obj_pin");178 if (strlen(file) > 50) {179 printf("file path too long: %s\n", file);180 exit(1);181 }182 ret = snprintf(rules, sizeof(rules),183 "iptables -A OUTPUT -m bpf --object-pinned %s -j ACCEPT",184 file);185 if (ret < 0 || ret >= sizeof(rules)) {186 printf("error constructing iptables command\n");187 exit(1);188 }189 ret = system(rules);190 if (ret < 0) {191 printf("iptables rule update failed: %d/n", WEXITSTATUS(ret));192 exit(1);193 }194}195 196static void print_table(void)197{198 struct stats curEntry;199 uint32_t curN = UINT32_MAX;200 uint32_t nextN;201 int res;202 203 while (bpf_map_get_next_key(map_fd, &curN, &nextN) > -1) {204 curN = nextN;205 res = bpf_map_lookup_elem(map_fd, &curN, &curEntry);206 if (res < 0) {207 error(1, errno, "fail to get entry value of Key: %u\n",208 curN);209 } else {210 printf("cookie: %u, uid: 0x%x, Packet Count: %lu,"211 " Bytes Count: %lu\n", curN, curEntry.uid,212 curEntry.packets, curEntry.bytes);213 }214 }215}216 217static void udp_client(void)218{219 struct sockaddr_in si_other = {0};220 struct sockaddr_in si_me = {0};221 struct stats dataEntry;222 int s_rcv, s_send, i, recv_len;223 char message = 'a';224 char buf;225 uint64_t cookie;226 int res;227 socklen_t cookie_len = sizeof(cookie);228 socklen_t slen = sizeof(si_other);229 230 s_rcv = socket(PF_INET, SOCK_DGRAM, 0);231 if (s_rcv < 0)232 error(1, errno, "rcv socket creat failed!\n");233 si_other.sin_family = AF_INET;234 si_other.sin_port = htons(PORT);235 if (inet_aton("127.0.0.1", &si_other.sin_addr) == 0)236 error(1, errno, "inet_aton\n");237 if (bind(s_rcv, (struct sockaddr *)&si_other, sizeof(si_other)) == -1)238 error(1, errno, "bind\n");239 s_send = socket(PF_INET, SOCK_DGRAM, 0);240 if (s_send < 0)241 error(1, errno, "send socket creat failed!\n");242 res = getsockopt(s_send, SOL_SOCKET, SO_COOKIE, &cookie, &cookie_len);243 if (res < 0)244 printf("get cookie failed: %s\n", strerror(errno));245 res = bpf_map_lookup_elem(map_fd, &cookie, &dataEntry);246 if (res != -1)247 error(1, errno, "socket stat found while flow not active\n");248 for (i = 0; i < 10; i++) {249 res = sendto(s_send, &message, sizeof(message), 0,250 (struct sockaddr *)&si_other, slen);251 if (res == -1)252 error(1, errno, "send\n");253 if (res != sizeof(message))254 error(1, 0, "%uB != %luB\n", res, sizeof(message));255 recv_len = recvfrom(s_rcv, &buf, sizeof(buf), 0,256 (struct sockaddr *)&si_me, &slen);257 if (recv_len < 0)258 error(1, errno, "receive\n");259 res = memcmp(&(si_other.sin_addr), &(si_me.sin_addr),260 sizeof(si_me.sin_addr));261 if (res != 0)262 error(1, EFAULT, "sender addr error: %d\n", res);263 printf("Message received: %c\n", buf);264 res = bpf_map_lookup_elem(map_fd, &cookie, &dataEntry);265 if (res < 0)266 error(1, errno, "lookup sk stat failed, cookie: %lu\n",267 cookie);268 printf("cookie: %lu, uid: 0x%x, Packet Count: %lu,"269 " Bytes Count: %lu\n\n", cookie, dataEntry.uid,270 dataEntry.packets, dataEntry.bytes);271 }272 close(s_send);273 close(s_rcv);274}275 276static int usage(void)277{278 printf("Usage: ./run_cookie_uid_helper_example.sh"279 " bpfObjName -option\n"280 " -t traffic monitor test\n"281 " -s getsockopt cookie test\n");282 return 1;283}284 285static void finish(int ret)286{287 test_finish = true;288}289 290int main(int argc, char *argv[])291{292 int opt;293 bool cfg_test_traffic = false;294 bool cfg_test_cookie = false;295 296 if (argc != 3)297 return usage();298 while ((opt = getopt(argc, argv, "ts")) != -1) {299 switch (opt) {300 case 't':301 cfg_test_traffic = true;302 break;303 case 's':304 cfg_test_cookie = true;305 break;306 307 default:308 printf("unknown option %c\n", opt);309 usage();310 return -1;311 }312 }313 maps_create();314 prog_load();315 prog_attach_iptables(argv[2]);316 if (cfg_test_traffic) {317 if (signal(SIGINT, finish) == SIG_ERR)318 error(1, errno, "register SIGINT handler failed");319 if (signal(SIGTERM, finish) == SIG_ERR)320 error(1, errno, "register SIGTERM handler failed");321 while (!test_finish) {322 print_table();323 printf("\n");324 sleep(1);325 }326 } else if (cfg_test_cookie) {327 udp_client();328 }329 close(prog_fd);330 close(map_fd);331 return 0;332}333