1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (c) 2014 Red Hat, Inc.
4 * Copyright (c) 2021 Petr Vorel <pvorel@suse.cz>
5 */
6
7 /*\
8 * [Description]
9 *
10 * Tests a netlink interface inside a new network namespace.
11 *
12 * - Unshares a network namespace (so network related actions
13 * have no effect on a real system).
14 * - Forks a child which creates a NETLINK_ROUTE netlink socket
15 * and listens to RTMGRP_LINK (network interface create/delete/up/down)
16 * multicast group.
17 * - Child then waits for parent approval to receive data from socket
18 * - Parent creates a new TAP interface (dummy0) and immediately
19 * removes it (which should generate some data in child's netlink socket).
20 * Then it allows child to continue.
21 * - As the child was listening to RTMGRP_LINK multicast group, it should
22 * detect the new interface creation/deletion (by reading data from netlink
23 * socket), if so, the test passes, otherwise it fails.
24 */
25
26 #define _GNU_SOURCE
27 #include <sys/wait.h>
28 #include <asm/types.h>
29 #include <sys/socket.h>
30 #include <linux/netlink.h>
31 #include <linux/rtnetlink.h>
32 #include <unistd.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <errno.h>
36
37 #include "tst_test.h"
38 #include "tst_safe_macros.h"
39 #include "lapi/sched.h"
40
41 #define MAX_TRIES 1000
42
child_func(void)43 static void child_func(void)
44 {
45 int fd, len, event_found, tries;
46 struct sockaddr_nl sa;
47 char buffer[4096];
48 struct nlmsghdr *nlh;
49
50 /* child will listen to a network interface create/delete/up/down events */
51 memset(&sa, 0, sizeof(sa));
52 sa.nl_family = AF_NETLINK;
53 sa.nl_groups = RTMGRP_LINK;
54
55 fd = SAFE_SOCKET(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
56 SAFE_BIND(fd, (struct sockaddr *) &sa, sizeof(sa));
57
58 /* waits for parent to create an interface */
59 TST_CHECKPOINT_WAKE_AND_WAIT(0);
60
61 /*
62 * To get rid of "resource temporarily unavailable" errors
63 * when testing with -i option
64 */
65 tries = 0;
66 event_found = 0;
67 nlh = (struct nlmsghdr *) buffer;
68 while (tries < MAX_TRIES) {
69 len = recv(fd, nlh, sizeof(buffer), MSG_DONTWAIT);
70 if (len > 0) {
71 /* stop receiving only on interface create/delete event */
72 if (nlh->nlmsg_type == RTM_NEWLINK ||
73 nlh->nlmsg_type == RTM_DELLINK) {
74 event_found++;
75 break;
76 }
77 }
78 usleep(10000);
79 tries++;
80 }
81
82 SAFE_CLOSE(fd);
83
84 if (event_found)
85 tst_res(TPASS, "interface changes detected");
86 else
87 tst_res(TFAIL, "failed to detect interface changes");
88
89 exit(0);
90 }
91
test_netns_netlink(void)92 static void test_netns_netlink(void)
93 {
94 /* unshares the network namespace */
95 SAFE_UNSHARE(CLONE_NEWNET);
96
97 if (SAFE_FORK() == 0)
98 child_func();
99
100 /* wait until child opens netlink socket */
101 TST_CHECKPOINT_WAIT(0);
102
103 /* creates TAP network interface dummy0 */
104 if (WEXITSTATUS(system("ip tuntap add dev dummy0 mode tap")))
105 tst_brk(TBROK, "adding interface failed");
106
107 /* removes previously created dummy0 device */
108 if (WEXITSTATUS(system("ip tuntap del mode tap dummy0")))
109 tst_brk(TBROK, "removing interface failed");
110
111 /* allow child to continue */
112 TST_CHECKPOINT_WAKE(0);
113
114 tst_reap_children();
115 }
116
117
118 static struct tst_test test = {
119 .test_all = test_netns_netlink,
120 .needs_checkpoints = 1,
121 .needs_root = 1,
122 .forks_child = 1,
123 .needs_kconfigs = (const char *[]) {
124 "CONFIG_NET_NS=y",
125 "CONFIG_TUN",
126 NULL
127 },
128 };
129