selftests/bpf: Move open_netns() and close_netns() into network_helpers.c

These will also be used by the xdp_do_redirect test being added in the next
commit.
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220309105346.100053-5-toke@redhat.com

tools/testing/selftests/bpf/network_helpers.c

 // SPDX-License-Identifier: GPL-2.0-only
+#define _GNU_SOURCE
+
 #include <errno.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
+#include <sched.h>
 
 #include <arpa/inet.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
 
 #include <linux/err.h>
 #include <linux/in.h>
 #include <linux/in6.h>
+#include <linux/limits.h>
 
 #include "bpf_util.h"
 #include "network_helpers.h"
+#include "test_progs.h"
 
 #define clean_errno() (errno == 0 ? "None" : strerror(errno))
 #define log_err(MSG, ...) ({						\
@@ -356,3 +363,82 @@ char *ping_command(int family)
 	}
 	return "ping";
 }
+
+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;
+
+	return 0;
+}
+
+struct nstoken *open_netns(const char *name)
+{
+	int nsfd;
+	char nspath[PATH_MAX];
+	int err;
+	struct nstoken *token;
+
+	token = malloc(sizeof(struct nstoken));
+	if (!ASSERT_OK_PTR(token, "malloc token"))
+		return NULL;
+
+	token->orig_netns_fd = open("/proc/self/ns/net", O_RDONLY);
+	if (!ASSERT_GE(token->orig_netns_fd, 0, "open /proc/self/ns/net"))
+		goto fail;
+
+	snprintf(nspath, sizeof(nspath), "%s/%s", "/var/run/netns", name);
+	nsfd = open(nspath, O_RDONLY | O_CLOEXEC);
+	if (!ASSERT_GE(nsfd, 0, "open netns fd"))
+		goto fail;
+
+	err = setns_by_fd(nsfd);
+	if (!ASSERT_OK(err, "setns_by_fd"))
+		goto fail;
+
+	return token;
+fail:
+	free(token);
+	return NULL;
+}
+
+void close_netns(struct nstoken *token)
+{
+	ASSERT_OK(setns_by_fd(token->orig_netns_fd), "setns_by_fd");
+	free(token);
+}

tools/testing/selftests/bpf/network_helpers.h

@@ -55,4 +55,13 @@ int make_sockaddr(int family, const char *addr_str, __u16 port,
 		  struct sockaddr_storage *addr, socklen_t *len);
 char *ping_command(int family);
 
+struct nstoken;
+/**
+ * open_netns() - Switch to specified network namespace by name.
+ *
+ * Returns token with which to restore the original namespace
+ * using close_netns().
+ */
+struct nstoken *open_netns(const char *name);
+void close_netns(struct nstoken *token);
 #endif

tools/testing/selftests/bpf/prog_tests/tc_redirect.c

@@ -10,8 +10,6 @@
  * to drop unexpected traffic.
  */
 
-#define _GNU_SOURCE
-
 #include <arpa/inet.h>
 #include <linux/if.h>
 #include <linux/if_tun.h>
@@ -19,10 +17,8 @@
 #include <linux/sysctl.h>
 #include <linux/time_types.h>
 #include <linux/net_tstamp.h>
-#include <sched.h>
 #include <stdbool.h>
 #include <stdio.h>
-#include <sys/mount.h>
 #include <sys/stat.h>
 #include <unistd.h>
 
@@ -92,91 +88,6 @@ static int write_file(const char *path, const char *newval)
 	return 0;
 }
 
-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;
-
-	return 0;
-}
-
-/**
- * open_netns() - Switch to specified network namespace by name.
- *
- * Returns token with which to restore the original namespace
- * using close_netns().
- */
-static struct nstoken *open_netns(const char *name)
-{
-	int nsfd;
-	char nspath[PATH_MAX];
-	int err;
-	struct nstoken *token;
-
-	token = calloc(1, sizeof(struct nstoken));
-	if (!ASSERT_OK_PTR(token, "malloc token"))
-		return NULL;
-
-	token->orig_netns_fd = open("/proc/self/ns/net", O_RDONLY);
-	if (!ASSERT_GE(token->orig_netns_fd, 0, "open /proc/self/ns/net"))
-		goto fail;
-
-	snprintf(nspath, sizeof(nspath), "%s/%s", "/var/run/netns", name);
-	nsfd = open(nspath, O_RDONLY | O_CLOEXEC);
-	if (!ASSERT_GE(nsfd, 0, "open netns fd"))
-		goto fail;
-
-	err = setns_by_fd(nsfd);
-	if (!ASSERT_OK(err, "setns_by_fd"))
-		goto fail;
-
-	return token;
-fail:
-	free(token);
-	return NULL;
-}
-
-static void close_netns(struct nstoken *token)
-{
-	ASSERT_OK(setns_by_fd(token->orig_netns_fd), "setns_by_fd");
-	free(token);
-}
-
 static int netns_setup_namespaces(const char *verb)
 {
 	const char * const *ns = namespaces;