/* Copyright (c) 2014 Red Hat, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of version 2 the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
***********************************************************************
* File: netns_netlink.c
*
* Tests a netlink interface inside a new network namespace.
* Description:
* 1. Unshares a network namespace (so network related actions
* have no effect on a real system)
* 2. Forks a child which creates a NETLINK_ROUTE netlink socket
* and listens to RTMGRP_LINK (network interface create/delete/up/down)
* multicast group.
* 4. Child then waits for parent approval to receive data from socket
* 3. Parent creates a new TAP interface (dummy0) and immediately
* removes it (which should generate some data in child's netlink socket).
* Then it allows child to continue.
* 4. As the child was listening to RTMGRP_LINK multicast group, it should
* detect the new interface creation/deletion (by reading data from netlink
* socket), if so, the test passes, otherwise it fails.
*/
#define _GNU_SOURCE
#include <sys/wait.h>
#include <asm/types.h>
#include <sys/socket.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include "netns_helper.h"
#include "test.h"
#include "safe_macros.h"
#define MAX_TRIES 1000
#define IP_TUNTAP_MIN_VER 100519
char *TCID = "netns_netlink";
int TST_TOTAL = 1;
static void cleanup(void)
{
tst_rmdir();
}
static void setup(void)
{
tst_require_root();
check_iproute(IP_TUNTAP_MIN_VER);
check_netns();
tst_tmpdir();
TST_CHECKPOINT_INIT(tst_rmdir);
}
int child_func(void)
{
int fd, len, event_found, tries;
struct sockaddr_nl sa;
char buffer[4096];
struct nlmsghdr *nlh;
/* child will listen to a network interface create/delete/up/down
* events */
memset(&sa, 0, sizeof(sa));
sa.nl_family = AF_NETLINK;
sa.nl_groups = RTMGRP_LINK;
fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (fd == -1) {
perror("socket");
return 1;
}
if (bind(fd, (struct sockaddr *) &sa, sizeof(sa)) == -1) {
perror("bind");
close(fd);
return 1;
}
/* waits for parent to create an interface */
TST_SAFE_CHECKPOINT_WAIT(NULL, 0);
/* To get rid of "resource temporarily unavailable" errors
* when testing with -i option */
tries = 0;
event_found = 0;
nlh = (struct nlmsghdr *) buffer;
while (tries < MAX_TRIES) {
len = recv(fd, nlh, sizeof(buffer), MSG_DONTWAIT);
if (len > 0) {
/* stop receiving only on interface create/delete
* event */
if (nlh->nlmsg_type == RTM_NEWLINK ||
nlh->nlmsg_type == RTM_DELLINK) {
event_found++;
break;
}
}
usleep(10000);
tries++;
}
close(fd);
if (!event_found) {
perror("recv");
return 1;
}
return 0;
}
static void test(void)
{
pid_t pid;
int status;
/* unshares the network namespace */
if (unshare(CLONE_NEWNET) == -1)
tst_brkm(TBROK | TERRNO, cleanup, "unshare failed");
pid = tst_fork();
if (pid < 0) {
tst_brkm(TBROK | TERRNO, cleanup, "fork failed");
}
if (pid == 0) {
_exit(child_func());
}
/* creates TAP network interface dummy0 */
if (WEXITSTATUS(system("ip tuntap add dev dummy0 mode tap")))
tst_brkm(TBROK, cleanup, "system() failed");
/* removes previously created dummy0 device */
if (WEXITSTATUS(system("ip tuntap del mode tap dummy0")))
tst_brkm(TBROK, cleanup, "system() failed");
/* allow child to continue */
TST_SAFE_CHECKPOINT_WAKE(cleanup, 0);
SAFE_WAITPID(cleanup, pid, &status, 0);
if (WIFEXITED(status) && WEXITSTATUS(status) != 0) {
tst_resm(TFAIL, "netlink interface fail");
return;
}
if (WIFSIGNALED(status)) {
tst_resm(TFAIL, "child was killed with signal %s",
tst_strsig(WTERMSIG(status)));
return;
}
tst_resm(TPASS, "netlink interface pass");
}
int main(int argc, char *argv[])
{
int lc;
tst_parse_opts(argc, argv, NULL, NULL);
setup();
for (lc = 0; TEST_LOOPING(lc); lc++)
test();
cleanup();
tst_exit();
}