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selftests/bpf: Remove the "/sys" mount and umount dance in {open,close}_netns

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The previous patches have removed the need to do the mount and umount
dance when switching netns. In particular:
* Avoid remounting /sys/fs/bpf to have a clean start
* Avoid remounting /sys to get a ifindex of a particular netns

This patch can finally remove the mount and umount dance in
{open,close}_netns which is unnecessarily complicated and
error-prone.

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20221129070900.3142427-6-martin.lau@linux.dev
This commit is contained in:
Martin KaFai Lau 2022-11-28 23:08:58 -08:00 committed by Daniel Borkmann
parent 5dc42a7fc2
commit 3084097c36
1 changed files with 5 additions and 46 deletions
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51
tools/testing/selftests/bpf/network_helpers.c
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@ -390,49 +390,6 @@ struct nstoken {
int orig_netns_fd;
};
static int setns_by_fd(int nsfd)
{
int err;
err = setns(nsfd, CLONE_NEWNET);
close(nsfd);
if (!ASSERT_OK(err, "setns"))
return err;
/* Switch /sys to the new namespace so that e.g. /sys/class/net
* reflects the devices in the new namespace.
*/
err = unshare(CLONE_NEWNS);
if (!ASSERT_OK(err, "unshare"))
return err;
/* Make our /sys mount private, so the following umount won't
* trigger the global umount in case it's shared.
*/
err = mount("none", "/sys", NULL, MS_PRIVATE, NULL);
if (!ASSERT_OK(err, "remount private /sys"))
return err;
err = umount2("/sys", MNT_DETACH);
if (!ASSERT_OK(err, "umount2 /sys"))
return err;
err = mount("sysfs", "/sys", "sysfs", 0, NULL);
if (!ASSERT_OK(err, "mount /sys"))
return err;
err = mount("bpffs", "/sys/fs/bpf", "bpf", 0, NULL);
if (!ASSERT_OK(err, "mount /sys/fs/bpf"))
return err;
err = mount("debugfs", "/sys/kernel/debug", "debugfs", 0, NULL);
if (!ASSERT_OK(err, "mount /sys/kernel/debug"))
return err;
return 0;
}
struct nstoken *open_netns(const char *name)
{
int nsfd;
@ -453,8 +410,9 @@ struct nstoken *open_netns(const char *name)
if (!ASSERT_GE(nsfd, 0, "open netns fd"))
goto fail;
err = setns_by_fd(nsfd);
if (!ASSERT_OK(err, "setns_by_fd"))
err = setns(nsfd, CLONE_NEWNET);
close(nsfd);
if (!ASSERT_OK(err, "setns"))
goto fail;
return token;
@ -465,6 +423,7 @@ fail:
void close_netns(struct nstoken *token)
{
ASSERT_OK(setns_by_fd(token->orig_netns_fd), "setns_by_fd");
ASSERT_OK(setns(token->orig_netns_fd, CLONE_NEWNET), "setns");
close(token->orig_netns_fd);
free(token);
}