62 lines · c
1// SPDX-License-Identifier: GPL-2.02#define _GNU_SOURCE3#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_COOKIE14#define SO_NETNS_COOKIE 7115#endif16 17#define pr_err(fmt, ...) \18 ({ \19 fprintf(stderr, "%s:%d:" fmt ": %m\n", \20 __func__, __LINE__, ##__VA_ARGS__); \21 1; \22 })23 24int 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