1 // SPDX-License-Identifier: GPL-2.0
2 #define _GNU_SOURCE
3 #include <sched.h>
4 #include <unistd.h>
5 #include <stdio.h>
6 #include <errno.h>
7 #include <string.h>
8 #include <stdlib.h>
9 #include <stdint.h>
10 #include <sys/types.h>
11 #include <sys/socket.h>
12
13 #ifndef SO_NETNS_COOKIE
14 #define SO_NETNS_COOKIE 71
15 #endif
16
17 #define pr_err(fmt, ...) \
18 ({ \
19 fprintf(stderr, "%s:%d:" fmt ": %m\n", \
20 __func__, __LINE__, ##__VA_ARGS__); \
21 1; \
22 })
23
24 int main(int argc, char *argvp[])
25 {
26 uint64_t cookie1, cookie2;
27 socklen_t vallen;
28 int sock1, sock2;
29
30 sock1 = socket(AF_INET, SOCK_STREAM, 0);
31 if (sock1 < 0)
32 return pr_err("Unable to create TCP socket");
33
34 vallen = sizeof(cookie1);
35 if (getsockopt(sock1, SOL_SOCKET, SO_NETNS_COOKIE, &cookie1, &vallen) != 0)
36 return pr_err("getsockopt(SOL_SOCKET, SO_NETNS_COOKIE)");
37
38 if (!cookie1)
39 return pr_err("SO_NETNS_COOKIE returned zero cookie");
40
41 if (unshare(CLONE_NEWNET))
42 return pr_err("unshare");
43
44 sock2 = socket(AF_INET, SOCK_STREAM, 0);
45 if (sock2 < 0)
46 return pr_err("Unable to create TCP socket");
47
48 vallen = sizeof(cookie2);
49 if (getsockopt(sock2, SOL_SOCKET, SO_NETNS_COOKIE, &cookie2, &vallen) != 0)
50 return pr_err("getsockopt(SOL_SOCKET, SO_NETNS_COOKIE)");
51
52 if (!cookie2)
53 return pr_err("SO_NETNS_COOKIE returned zero cookie");
54
55 if (cookie1 == cookie2)
56 return pr_err("SO_NETNS_COOKIE returned identical cookies for distinct ns");
57
58 close(sock1);
59 close(sock2);
60 return 0;
61 }
62
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.