tests: fix unix domain socket decoding availability test

Since inet_diag and unix_diag interfaces are implemented by different
kernel modules, they have to be tested separately.

* tests/netlink_unix_diag.c: New file.
* tests/unix-yy.test: Use it.
* tests/Makefile.am (check_PROGRAMS): Add it.
* tests/.gitignore: Likewise.

tests/.gitignore

@@ -3,6 +3,7 @@ inet-accept-connect-send-recv
 mmsg
 net-accept-connect
 netlink_inet_diag
+netlink_unix_diag
 scm_rights
 set_ptracer_any
 sigaction

tests/Makefile.am

@@ -8,6 +8,7 @@ check_PROGRAMS = \
 	mmsg \
 	net-accept-connect \
 	netlink_inet_diag \
+	netlink_unix_diag \
 	scm_rights \
 	set_ptracer_any \
 	sigaction \

tests/netlink_unix_diag.c

@@ -0,0 +1,98 @@
+#include <assert.h>
+#include <stddef.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <linux/netlink.h>
+#include <linux/sock_diag.h>
+#include <linux/unix_diag.h>
+
+static int
+send_query(const int fd, const int family, const int proto)
+{
+	struct sockaddr_nl nladdr = {
+		.nl_family = AF_NETLINK
+	};
+	struct {
+		struct nlmsghdr nlh;
+		struct unix_diag_req udr;
+	} req = {
+		.nlh = {
+			.nlmsg_len = sizeof(req),
+			.nlmsg_type = SOCK_DIAG_BY_FAMILY,
+			.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST
+		},
+		.udr = {
+			.sdiag_family = family,
+			.sdiag_protocol = proto,
+			.udiag_states = -1,
+			.udiag_show = UDIAG_SHOW_NAME | UDIAG_SHOW_PEER
+		}
+	};
+	struct iovec iov = {
+		.iov_base = &req,
+		.iov_len = sizeof(req)
+	};
+	struct msghdr msg = {
+		.msg_name = (void*)&nladdr,
+		.msg_namelen = sizeof(nladdr),
+		.msg_iov = &iov,
+		.msg_iovlen = 1
+	};
+
+	return sendmsg(fd, &msg, 0) > 0;
+}
+
+static int
+check_responses(const int fd)
+{
+	static char buf[8192];
+	struct sockaddr_nl nladdr = {
+		.nl_family = AF_NETLINK
+	};
+	struct iovec iov = {
+		.iov_base = buf,
+		.iov_len = sizeof(buf)
+	};
+	struct msghdr msg = {
+		.msg_name = (void*)&nladdr,
+		.msg_namelen = sizeof(nladdr),
+		.msg_iov = &iov,
+		.msg_iovlen = 1
+	};
+
+	ssize_t ret = recvmsg(fd, &msg, 0);
+	if (ret <= 0)
+		return 0;
+
+	struct nlmsghdr *h = (struct nlmsghdr*)buf;
+	return (NLMSG_OK(h, ret) &&
+		h->nlmsg_type != NLMSG_ERROR &&
+		h->nlmsg_type != NLMSG_DONE) ? 1 : 0;
+}
+
+#define SUN_PATH "netlink_unix_diag_socket"
+int main(void)
+{
+	struct sockaddr_un addr = {
+		.sun_family = AF_UNIX,
+		.sun_path = SUN_PATH
+	};
+	socklen_t len = offsetof(struct sockaddr_un, sun_path) + sizeof(SUN_PATH);
+
+	close(0);
+	close(1);
+
+	(void) unlink(SUN_PATH);
+	assert(socket(PF_LOCAL, SOCK_STREAM, 0) == 0);
+	assert(bind(0, (struct sockaddr *) &addr, len) == 0);
+	assert(listen(0, 5) == 0);
+	assert(unlink(SUN_PATH) == 0);
+
+	if (socket(AF_NETLINK, SOCK_RAW, NETLINK_SOCK_DIAG) != 1)
+		return 77;
+
+	return (send_query(1, AF_UNIX, 0) &&
+		check_responses(1)) ? 0 : 77;
+}

tests/unix-yy.test

@@ -17,11 +17,11 @@ rm -f $LOG.* $LOG-*
 ./net-accept-connect ||
 	fail_ 'net-accept-connect failed'
 
-./netlink_inet_diag || {
+./netlink_unix_diag || {
 	if [ $? -eq 77 ]; then
-		framework_skip_ 'NETLINK_INET_DIAG is not available'
+		framework_skip_ 'NETLINK_SOCK_DIAG for unix domain sockets is not available'
 	else
-		fail_ 'netlink_inet_diag failed'
+		fail_ 'netlink_unix_diag failed'
 	fi
 }