Regards,
Keith

On Sep 20, 2016, at 12:05 AM, Yuanhan Liu [off-list ref] wrote:

[ just got few more comments after some fiddling with the build issue ]

On Fri, Sep 16, 2016 at 11:22:13AM -0500, Keith Wiles wrote:

quoted

diff --git a/drivers/net/tap/Makefile b/drivers/net/tap/Makefile
new file mode 100644
index 0000000..442a2fe
--- /dev/null
+++ b/drivers/net/tap/Makefile

@@ -0,0 +1,60 @@
+#   BSD LICENSE
+#
+#   Copyright(c) 2014 John W. Linville <linville@redhat.com>
+#   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
+#   Copyright(c) 2014 6WIND S.A.

Just wondering, is it on purpose, or just yet another copy-paste error?

Yes, I will send another patch to fix this one.

quoted

+#include <arpa/inet.h>
+#include <net/if.h>
+#ifdef __linux__

So, you meant to add other OS support, say BSD?

I did not mean to support BSD, just Linux and I will remove the ifdef to reflect it. If you look at the configuration file I only added it to the common_linux file and not BSD.

The concern I am having is on my standard Ubuntu 16.04 system these errors do not appear. I would like to understand why they appeared on your system. The ifdef __linux__ must be enabled as the defines in the linux/if_tun.h file do not give an error. I did play with the headers already and removed the ifdef, but as I could not reproduce your build failure it did not trigger anything new.

I will look at it some more, but it does not make sense and I do want to make sure it works.

quoted

+#include <linux/if.h>
+#include <linux/if_tun.h>
+#include <linux/if_ether.h>
+#else
+#include <netinet/if_ether.h>
+#endif
+#include <fcntl.h>
+
+#include <poll.h>
+
+/* Linux based path to the TUN device */
+#define TUN_TAP_DEV_PATH        "/dev/net/tun"

However, you hardcoded a linux only path here. While checking the code
from qemu, I saw that the path is actually different from different UNIX
variants, even for FreeBSD and NetBSD.

I only assumed this to work for Linux and not FreeBSD/NetBSD as the handling of the opens on the tun device are different then linux. I also only added it to the common_linux configuration file.

   [yliu@yliu-dev ~/qemu]$ grep -E "/dev/.*(tap|tun)" net/tap*.c
   net/tap-bsd.c:            snprintf(dname, sizeof dname, "/dev/tun%d", i);
   net/tap-bsd.c:            snprintf(dname, sizeof dname, "/dev/tap%d", i);
   net/tap-bsd.c:#define PATH_NET_TAP "/dev/tap"
   net/tap-linux.c:#define PATH_NET_TUN "/dev/net/tun"
   net/tap-solaris.c:    TFR(tap_fd = open("/dev/tap", O_RDWR, 0));
   ...

	--yliu