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1/* This test is a demo of using get_socket_uid and get_socket_cookie
2 * helper function to do per socket based network traffic monitoring.
3 * It requires iptables version higher then 1.6.1. to load pinned eBPF
4 * program into the xt_bpf match.
5 *
6 * TEST:
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7 * ./run_cookie_uid_helper_example.sh -option
8 * option:
9 * -t: do traffic monitoring test, the program will continuously
10 * print out network traffic happens after program started A sample
11 * output is shown below:
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12 *
13 * cookie: 877, uid: 0x3e8, Pakcet Count: 20, Bytes Count: 11058
14 * cookie: 132, uid: 0x0, Pakcet Count: 2, Bytes Count: 286
15 * cookie: 812, uid: 0x3e8, Pakcet Count: 3, Bytes Count: 1726
16 * cookie: 802, uid: 0x3e8, Pakcet Count: 2, Bytes Count: 104
17 * cookie: 877, uid: 0x3e8, Pakcet Count: 20, Bytes Count: 11058
18 * cookie: 831, uid: 0x3e8, Pakcet Count: 2, Bytes Count: 104
19 * cookie: 0, uid: 0x0, Pakcet Count: 6, Bytes Count: 712
20 * cookie: 880, uid: 0xfffe, Pakcet Count: 1, Bytes Count: 70
21 *
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22 * -s: do getsockopt SO_COOKIE test, the program will set up a pair of
23 * UDP sockets and send packets between them. And read out the traffic data
24 * directly from the ebpf map based on the socket cookie.
25 *
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26 * Clean up: if using shell script, the script file will delete the iptables
27 * rule and unmount the bpf program when exit. Else the iptables rule need
28 * to be deleted by hand, see run_cookie_uid_helper_example.sh for detail.
29 */
30
31#define _GNU_SOURCE
32
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>
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42#include <net/if.h>
43#include <signal.h>
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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>
8d930450 54#include "bpf_insn.h"
51570a5a 55
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56#define PORT 8888
57
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58struct stats {
59 uint32_t uid;
60 uint64_t packets;
61 uint64_t bytes;
62};
63
64static int map_fd, prog_fd;
65
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66static bool test_finish;
67
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68static void maps_create(void)
69{
70 map_fd = bpf_create_map(BPF_MAP_TYPE_HASH, sizeof(uint32_t),
71 sizeof(struct stats), 100, 0);
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 will
83 * 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_buff
89 */
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 cookie
106 * stored already
107 * 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 sequentially
115 * place the member value into the memory. Packets value
116 * 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,
eb6211d3 119 -32 + (__s16)offsetof(struct stats, uid)),
51570a5a 120 BPF_ST_MEM(BPF_DW, BPF_REG_10,
eb6211d3 121 -32 + (__s16)offsetof(struct stats, packets), 1),
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122 /*
123 * __sk_buff is a special struct used for eBPF program to
124 * 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,
eb6211d3 129 -32 + (__s16)offsetof(struct stats, bytes)),
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130 /*
131 * add new map entry using BPF_FUNC_map_update_elem, it takes
132 * 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 can
145 * be done by directly write to pointers instead of using
146 * BPF_FUNC_map_update_elem helper function
147 */
148 BPF_MOV64_REG(BPF_REG_9, BPF_REG_0),
149 BPF_MOV64_IMM(BPF_REG_1, 1),
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150 BPF_ATOMIC_OP(BPF_DW, BPF_ADD, BPF_REG_9, BPF_REG_1,
151 offsetof(struct stats, packets)),
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152 BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_6,
153 offsetof(struct __sk_buff, len)),
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154 BPF_ATOMIC_OP(BPF_DW, BPF_ADD, BPF_REG_9, BPF_REG_1,
155 offsetof(struct stats, bytes)),
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156 BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_6,
157 offsetof(struct __sk_buff, len)),
158 BPF_EXIT_INSN(),
159 };
160 prog_fd = bpf_load_program(BPF_PROG_TYPE_SOCKET_FILTER, prog,
161 ARRAY_SIZE(prog), "GPL", 0,
162 log_buf, sizeof(log_buf));
163 if (prog_fd < 0)
164 error(1, errno, "failed to load prog\n%s\n", log_buf);
165}
166
167static void prog_attach_iptables(char *file)
168{
169 int ret;
50b796e6 170 char rules[256];
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171
172 if (bpf_obj_pin(prog_fd, file))
173 error(1, errno, "bpf_obj_pin");
174 if (strlen(file) > 50) {
175 printf("file path too long: %s\n", file);
176 exit(1);
177 }
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178 ret = snprintf(rules, sizeof(rules),
179 "iptables -A OUTPUT -m bpf --object-pinned %s -j ACCEPT",
180 file);
181 if (ret < 0 || ret >= sizeof(rules)) {
182 printf("error constructing iptables command\n");
183 exit(1);
184 }
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185 ret = system(rules);
186 if (ret < 0) {
187 printf("iptables rule update failed: %d/n", WEXITSTATUS(ret));
188 exit(1);
189 }
190}
191
192static void print_table(void)
193{
194 struct stats curEntry;
195 uint32_t curN = UINT32_MAX;
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196 uint32_t nextN;
197 int res;
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198
199 while (bpf_map_get_next_key(map_fd, &curN, &nextN) > -1) {
200 curN = nextN;
201 res = bpf_map_lookup_elem(map_fd, &curN, &curEntry);
202 if (res < 0) {
203 error(1, errno, "fail to get entry value of Key: %u\n",
204 curN);
205 } else {
206 printf("cookie: %u, uid: 0x%x, Packet Count: %lu,"
207 " Bytes Count: %lu\n", curN, curEntry.uid,
208 curEntry.packets, curEntry.bytes);
209 }
210 }
211}
212
00f660ea 213static void udp_client(void)
51570a5a 214{
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215 struct sockaddr_in si_other = {0};
216 struct sockaddr_in si_me = {0};
217 struct stats dataEntry;
218 int s_rcv, s_send, i, recv_len;
219 char message = 'a';
220 char buf;
221 uint64_t cookie;
222 int res;
223 socklen_t cookie_len = sizeof(cookie);
224 socklen_t slen = sizeof(si_other);
225
226 s_rcv = socket(PF_INET, SOCK_DGRAM, 0);
227 if (s_rcv < 0)
228 error(1, errno, "rcv socket creat failed!\n");
229 si_other.sin_family = AF_INET;
230 si_other.sin_port = htons(PORT);
231 if (inet_aton("127.0.0.1", &si_other.sin_addr) == 0)
232 error(1, errno, "inet_aton\n");
233 if (bind(s_rcv, (struct sockaddr *)&si_other, sizeof(si_other)) == -1)
234 error(1, errno, "bind\n");
235 s_send = socket(PF_INET, SOCK_DGRAM, 0);
236 if (s_send < 0)
237 error(1, errno, "send socket creat failed!\n");
238 res = getsockopt(s_send, SOL_SOCKET, SO_COOKIE, &cookie, &cookie_len);
239 if (res < 0)
240 printf("get cookie failed: %s\n", strerror(errno));
241 res = bpf_map_lookup_elem(map_fd, &cookie, &dataEntry);
242 if (res != -1)
243 error(1, errno, "socket stat found while flow not active\n");
244 for (i = 0; i < 10; i++) {
245 res = sendto(s_send, &message, sizeof(message), 0,
246 (struct sockaddr *)&si_other, slen);
247 if (res == -1)
248 error(1, errno, "send\n");
249 if (res != sizeof(message))
250 error(1, 0, "%uB != %luB\n", res, sizeof(message));
251 recv_len = recvfrom(s_rcv, &buf, sizeof(buf), 0,
252 (struct sockaddr *)&si_me, &slen);
253 if (recv_len < 0)
20cfb7a0 254 error(1, errno, "receive\n");
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255 res = memcmp(&(si_other.sin_addr), &(si_me.sin_addr),
256 sizeof(si_me.sin_addr));
257 if (res != 0)
258 error(1, EFAULT, "sender addr error: %d\n", res);
259 printf("Message received: %c\n", buf);
260 res = bpf_map_lookup_elem(map_fd, &cookie, &dataEntry);
261 if (res < 0)
262 error(1, errno, "lookup sk stat failed, cookie: %lu\n",
263 cookie);
264 printf("cookie: %lu, uid: 0x%x, Packet Count: %lu,"
265 " Bytes Count: %lu\n\n", cookie, dataEntry.uid,
266 dataEntry.packets, dataEntry.bytes);
51570a5a 267 }
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268 close(s_send);
269 close(s_rcv);
270}
51570a5a 271
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272static int usage(void)
273{
274 printf("Usage: ./run_cookie_uid_helper_example.sh"
275 " bpfObjName -option\n"
276 " -t traffic monitor test\n"
277 " -s getsockopt cookie test\n");
278 return 1;
279}
51570a5a 280
4784726f 281static void finish(int ret)
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282{
283 test_finish = true;
284}
285
286int main(int argc, char *argv[])
287{
288 int opt;
289 bool cfg_test_traffic = false;
290 bool cfg_test_cookie = false;
291
292 if (argc != 3)
293 return usage();
294 while ((opt = getopt(argc, argv, "ts")) != -1) {
295 switch (opt) {
296 case 't':
297 cfg_test_traffic = true;
298 break;
299 case 's':
300 cfg_test_cookie = true;
301 break;
51570a5a 302
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303 default:
304 printf("unknown option %c\n", opt);
305 usage();
306 return -1;
307 }
308 }
309 maps_create();
310 prog_load();
311 prog_attach_iptables(argv[2]);
312 if (cfg_test_traffic) {
313 if (signal(SIGINT, finish) == SIG_ERR)
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314 error(1, errno, "register SIGINT handler failed");
315 if (signal(SIGTERM, finish) == SIG_ERR)
316 error(1, errno, "register SIGTERM handler failed");
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317 while (!test_finish) {
318 print_table();
319 printf("\n");
320 sleep(1);
1132b998 321 }
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322 } else if (cfg_test_cookie) {
323 udp_client();
324 }
325 close(prog_fd);
326 close(map_fd);
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327 return 0;
328}