selftests/bpf: Add tests for cgroup unix socket address hooks

These selftests are written in prog_tests style instead of adding
them to the existing test_sock_addr tests. Migrating the existing
sock addr tests to prog_tests style is left for future work. This
commit adds support for testing bind() sockaddr hooks, even though
there's no unix socket sockaddr hook for bind(). We leave this code
intact for when the INET and INET6 tests are migrated in the future
which do support intercepting bind().

Signed-off-by: Daan De Meyer <daan.j.demeyer@gmail.com>
Link: https://lore.kernel.org/r/20231011185113.140426-10-daan.j.demeyer@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

1 files changed, 34 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c
index da72a3a66230..6db27a9088e9 100644
--- a/tools/testing/selftests/bpf/network_helpers.c
+++ b/tools/testing/selftests/bpf/network_helpers.c
@@ -11,6 +11,7 @@
 #include <arpa/inet.h>
 #include <sys/mount.h>
 #include <sys/stat.h>
+#include <sys/un.h>
 
 #include <linux/err.h>
 #include <linux/in.h>
@@ -257,6 +258,26 @@ static int connect_fd_to_addr(int fd,
 	return 0;
 }
 
+int connect_to_addr(const struct sockaddr_storage *addr, socklen_t addrlen, int type)
+{
+	int fd;
+
+	fd = socket(addr->ss_family, type, 0);
+	if (fd < 0) {
+		log_err("Failed to create client socket");
+		return -1;
+	}
+
+	if (connect_fd_to_addr(fd, addr, addrlen, false))
+		goto error_close;
+
+	return fd;
+
+error_close:
+	save_errno_close(fd);
+	return -1;
+}
+
 static const struct network_helper_opts default_opts;
 
 int connect_to_fd_opts(int server_fd, const struct network_helper_opts *opts)
@@ -380,6 +401,19 @@ int make_sockaddr(int family, const char *addr_str, __u16 port,
 		if (len)
 			*len = sizeof(*sin6);
 		return 0;
+	} else if (family == AF_UNIX) {
+		/* Note that we always use abstract unix sockets to avoid having
+		 * to clean up leftover files.
+		 */
+		struct sockaddr_un *sun = (void *)addr;
+
+		memset(addr, 0, sizeof(*sun));
+		sun->sun_family = family;
+		sun->sun_path[0] = 0;
+		strcpy(sun->sun_path + 1, addr_str);
+		if (len)
+			*len = offsetof(struct sockaddr_un, sun_path) + 1 + strlen(addr_str);
+		return 0;
 	}
 	return -1;
 }