selftests: net: af_unix: Test connect() with different netns.

This patch add a test that checks connect()ivity between two sockets:

    unnamed socket -> bound socket
                      * SOCK_STREAM or SOCK_DGRAM
                      * pathname or abstract
                      * same or different netns

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

tools/testing/selftests/net/.gitignore

@@ -37,3 +37,4 @@ gro
 ioam6_parser
 toeplitz
 cmsg_sender
+unix_connect

tools/testing/selftests/net/af_unix/Makefile

@@ -1,2 +1,3 @@
-TEST_GEN_PROGS := test_unix_oob
+TEST_GEN_PROGS := test_unix_oob unix_connect
+
 include ../../lib.mk

tools/testing/selftests/net/af_unix/unix_connect.c

@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+#include <sched.h>
+
+#include <stdio.h>
+#include <unistd.h>
+
+#include <sys/socket.h>
+#include <sys/un.h>
+
+#include "../../kselftest_harness.h"
+
+FIXTURE(unix_connect)
+{
+	int server, client;
+	int family;
+};
+
+FIXTURE_VARIANT(unix_connect)
+{
+	int type;
+	char sun_path[8];
+	int len;
+	int flags;
+	int err;
+};
+
+FIXTURE_VARIANT_ADD(unix_connect, stream_pathname)
+{
+	.type = SOCK_STREAM,
+	.sun_path = "test",
+	.len = 4 + 1,
+	.flags = 0,
+	.err = 0,
+};
+
+FIXTURE_VARIANT_ADD(unix_connect, stream_abstract)
+{
+	.type = SOCK_STREAM,
+	.sun_path = "\0test",
+	.len = 5,
+	.flags = 0,
+	.err = 0,
+};
+
+FIXTURE_VARIANT_ADD(unix_connect, stream_pathname_netns)
+{
+	.type = SOCK_STREAM,
+	.sun_path = "test",
+	.len = 4 + 1,
+	.flags = CLONE_NEWNET,
+	.err = 0,
+};
+
+FIXTURE_VARIANT_ADD(unix_connect, stream_abstract_netns)
+{
+	.type = SOCK_STREAM,
+	.sun_path = "\0test",
+	.len = 5,
+	.flags = CLONE_NEWNET,
+	.err = ECONNREFUSED,
+};
+
+FIXTURE_VARIANT_ADD(unix_connect, dgram_pathname)
+{
+	.type = SOCK_DGRAM,
+	.sun_path = "test",
+	.len = 4 + 1,
+	.flags = 0,
+	.err = 0,
+};
+
+FIXTURE_VARIANT_ADD(unix_connect, dgram_abstract)
+{
+	.type = SOCK_DGRAM,
+	.sun_path = "\0test",
+	.len = 5,
+	.flags = 0,
+	.err = 0,
+};
+
+FIXTURE_VARIANT_ADD(unix_connect, dgram_pathname_netns)
+{
+	.type = SOCK_DGRAM,
+	.sun_path = "test",
+	.len = 4 + 1,
+	.flags = CLONE_NEWNET,
+	.err = 0,
+};
+
+FIXTURE_VARIANT_ADD(unix_connect, dgram_abstract_netns)
+{
+	.type = SOCK_DGRAM,
+	.sun_path = "\0test",
+	.len = 5,
+	.flags = CLONE_NEWNET,
+	.err = ECONNREFUSED,
+};
+
+FIXTURE_SETUP(unix_connect)
+{
+	self->family = AF_UNIX;
+}
+
+FIXTURE_TEARDOWN(unix_connect)
+{
+	close(self->server);
+	close(self->client);
+
+	if (variant->sun_path[0])
+		remove("test");
+}
+
+#define offsetof(type, member) ((size_t)&((type *)0)->(member))
+
+TEST_F(unix_connect, test)
+{
+	socklen_t addrlen;
+	struct sockaddr_un addr = {
+		.sun_family = self->family,
+	};
+	int err;
+
+	self->server = socket(self->family, variant->type, 0);
+	ASSERT_NE(-1, self->server);
+
+	addrlen = offsetof(struct sockaddr_un, sun_path) + variant->len;
+	memcpy(&addr.sun_path, variant->sun_path, variant->len);
+
+	err = bind(self->server, (struct sockaddr *)&addr, addrlen);
+	ASSERT_EQ(0, err);
+
+	if (variant->type == SOCK_STREAM) {
+		err = listen(self->server, 32);
+		ASSERT_EQ(0, err);
+	}
+
+	err = unshare(variant->flags);
+	ASSERT_EQ(0, err);
+
+	self->client = socket(self->family, variant->type, 0);
+	ASSERT_LT(0, self->client);
+
+	err = connect(self->client, (struct sockaddr *)&addr, addrlen);
+	ASSERT_EQ(variant->err, err == -1 ? errno : 0);
+}
+
+TEST_HARNESS_MAIN