[PATCH v3 2/7] can: Add can_common.h for vcan device setup

[Richard Palethorpe <rpalethorpe@suse.com>]

Note that we call modprobe to set echo=1. However this does seem to be
necessary for the current tests on 5.10. It has been kept to avoid
changing the test behavior unnecessarily, but can most likely be
safely removed if it causes problems.

Signed-off-by: Richard Palethorpe <rpalethorpe@suse.com>
---
 .../network/can/filter-tests/can_common.h     | 75 +++++++++++++++++++
 1 file changed, 75 insertions(+)
 create mode 100644 testcases/network/can/filter-tests/can_common.h

diff --git a/testcases/network/can/filter-tests/can_common.h b/testcases/network/can/filter-tests/can_common.h
new file mode 100644
index 000000000..f15145f30
--- /dev/null
+++ b/testcases/network/can/filter-tests/can_common.h
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2021 SUSE LLC
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+#include <sys/time.h>
+
+#include "tst_cmd.h"
+#include "tst_safe_stdio.h"
+#include "tst_safe_file_ops.h"
+
+#include <linux/if.h>
+#include <linux/can.h>
+#include <linux/can/raw.h>
+
+#ifndef IFF_ECHO
+# define IFF_ECHO (1<<18)
+#endif
+
+static char *can_dev_name;
+static int can_created_dev;
+
+static void can_cmd(const char *const argv[])
+{
+	tst_cmd(argv, NULL, NULL, TST_CMD_TCONF_ON_MISSING);
+}
+
+#define CAN_CMD(...) can_cmd((const char *const[]){ __VA_ARGS__, NULL })
+
+static void can_setup_vcan(void)
+{
+	unsigned int flags;
+	char *path;
+
+	if (can_dev_name)
+		goto check_echo;
+
+	can_dev_name = "vcan0";
+
+	tst_res(TINFO, "Creating vcan0 device; use -D option to avoid this");
+
+	CAN_CMD("modprobe", "-r", "vcan");
+	CAN_CMD("modprobe", "vcan", "echo=1");
+
+	can_created_dev = 1;
+
+	CAN_CMD("ip", "link", "add", "dev", "vcan0", "type", "vcan");
+	CAN_CMD("ip", "link", "set", "dev", "vcan0", "up");
+
+check_echo:
+	/* Precondition for the frame flow test? */
+	SAFE_ASPRINTF(&path, "/sys/class/net/%s/flags", can_dev_name);
+	if (FILE_SCANF(path, "%x", &flags) || !(flags & IFF_ECHO)) {
+		tst_res(TWARN, "Could not determine if ECHO is set on %s",
+			can_dev_name);
+	}
+}
+
+static void can_cleanup_vcan(void)
+{
+	if (!can_created_dev)
+		return;
+
+	CAN_CMD("ip", "link", "set", "dev", "vcan0", "down");
+	CAN_CMD("ip", "link", "del", "dev", "vcan0");
+	CAN_CMD("modprobe", "-r", "vcan");
+}
-- 
2.30.0