datapath-windows: return TRUE on success in NlAttrValidate

Signed-off-by: Nithin Raju <nithin@vmware.com>
Acked-by: Samuel Ghinet <sghinet@cloudbasesolutions.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
datapath-windows: add OvsCompareString() to compare strings

In this patch we implement a utility function to compare ANSI
strings using the Rtl* functions. As much as possible, in an
NDIS driver, we stick to Rtl* functions for memory/string
manipulation.

Signed-off-by: Nithin Raju <nithin@vmware.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
lib/netlink-socket.c: add support for nl_transact() on Windows

In this patch, we add support for nl_transact() on Windows using
the OVS_IOCTL_TRANSACT ioctl that sends down the request and gets
the reply in the same call to the kernel.

This is obviously a digression from the way it is implemented in
Linux where all the sends are done at once using sendmsg() and
replies are received one at a time.

Initial implementation was in the Linux way using multiple writes
followed by reads, but decided against it since it is not efficient
and also it complicates the state machine in the kernel.

The Windows implementation has equivalent code for handling corner
cases and error coditions similar to Linux. Some of it is not
applicable yet. Eg. the Windows kernel does not embed an error
in the netlink message itself. There's userspace code nevertheless
for this.

Signed-off-by: Nithin Raju <nithin@vmware.com>
Acked-by: Samuel Ghinet <sghinet@cloudbasesolutions.com>
Acked-by: Eitan Eliahu <eliahue@vmware.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
extract-odp-netlink-windows-dp-h: add definition of IFNAMSIZ

The Windows kernel datapath needs the definition of 'IFNAMSIZ' for
specifying attribute sizes in netlink policies. Adding the definition
of 'IFNAMSIZ' to be part of OvsDpInterface.h similar to ETH_ADDR_LEN.

Signed-off-by: Nithin Raju <nithin@vmware.com>
Acked-by: Samuel Ghinet <sghinet@cloudbasesolutions.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
datapath-windows: add OVS_DP_CMD_SET and OVS_DP_CMD_GET transaction support

In this patch, we add support for two commands, both of them are issued
as part of transactions semantics from userspace:
1. OVS_DP_CMD_SET is used to get the properties of a DP as well as set
some properties. The set operations does not seem to make much sense for
the Windows datpath right now.
2. There's already support for OVS_DP_CMD_GET command issued via the
dump semantics from userspace. Turns out that userspace can issue
OVS_DP_CMD_GET as a transaction.

There's lot of common code between these two commands. Hence combining
the implementation and the review.

Also refactories some of the code in the implementation of dump-based
OVS_DP_CMD_GET, and updated some of the comments.

Validation:
- With these series of patches, I was able to run the following command:
> .\utilities\ovs-dpctl.exe show
system@ovs-system:
    lookups: hit:0 missed:22 lost:0
    flows: 0
- I got so far as to hit the PORT_DUMP command which is currently not
implemented.

Signed-off-by: Nithin Raju <nithin@vmware.com>
Tested-by: Nithin Raju <nithin@vmware.com>
Reported-at: https://github.com/openvswitch/ovs-issues/issues/38
Acked-by: Samuel Ghinet <sghinet@cloudbasesolutions.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>