selftests: udp: test for passing SO_MARK as cmsg

Before fix:
|  Case IPv6 rejection returned 0, expected 1
|FAIL - 1/4 cases failed

With the fix:
| OK

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 67 insertions, 0 deletions

diff --git a/tools/testing/selftests/net/cmsg_so_mark.c b/tools/testing/selftests/net/cmsg_so_mark.c
new file mode 100644
index 000000000000..27f2804892a7
--- /dev/null
+++ b/tools/testing/selftests/net/cmsg_so_mark.c
@@ -0,0 +1,67 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <errno.h>
+#include <netdb.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <linux/types.h>
+#include <sys/socket.h>
+
+int main(int argc, const char **argv)
+{
+	char cbuf[CMSG_SPACE(sizeof(__u32))];
+	struct addrinfo hints, *ai;
+	struct cmsghdr *cmsg;
+	struct iovec iov[1];
+	struct msghdr msg;
+	int mark;
+	int err;
+	int fd;
+
+	if (argc != 4) {
+		fprintf(stderr, "Usage: %s <dst_ip> <port> <mark>\n", argv[0]);
+		return 1;
+	}
+	mark = atoi(argv[3]);
+
+	memset(&hints, 0, sizeof(hints));
+	hints.ai_family = AF_UNSPEC;
+	hints.ai_socktype = SOCK_DGRAM;
+
+	ai = NULL;
+	err = getaddrinfo(argv[1], argv[2], &hints, &ai);
+	if (err) {
+		fprintf(stderr, "Can't resolve address: %s\n", strerror(errno));
+		return 1;
+	}
+
+	fd = socket(ai->ai_family, SOCK_DGRAM, IPPROTO_UDP);
+	if (fd < 0) {
+		fprintf(stderr, "Can't open socket: %s\n", strerror(errno));
+		freeaddrinfo(ai);
+		return 1;
+	}
+
+	iov[0].iov_base = "bla";
+	iov[0].iov_len = 4;
+
+	msg.msg_name = ai->ai_addr;
+	msg.msg_namelen = ai->ai_addrlen;
+	msg.msg_iov = iov;
+	msg.msg_iovlen = 1;
+	msg.msg_control = cbuf;
+	msg.msg_controllen = sizeof(cbuf);
+
+	cmsg = CMSG_FIRSTHDR(&msg);
+	cmsg->cmsg_level = SOL_SOCKET;
+	cmsg->cmsg_type = SO_MARK;
+	cmsg->cmsg_len = CMSG_LEN(sizeof(__u32));
+	*(__u32 *)CMSG_DATA(cmsg) = mark;
+
+	err = sendmsg(fd, &msg, 0);
+
+	close(fd);
+	freeaddrinfo(ai);
+	return err != 4;
+}