From fd972eb87a888242fb1a8ec2394fa7b3030fbd7d Mon Sep 17 00:00:00 2001
From: Nithin Raju <nithin@vmware.com>
Date: Wed, 27 Aug 2014 08:36:19 -0700
Subject: [PATCH] netlink-socket: Use read/write ioctl instead of
 ReadFile/WriteFile.

The Windows datapath supports a READ/WRITE ioctl instead of ReadFile/WriteFile.
In this change, we update the following:
- WriteFile() in nl_sock_send__() to use DeviceIoControl(OVS_IOCTL_WRITE)
- ReadFile() in nl_sock_recv__() to use DeviceIoControl(OVS_IOCTL_READ)

The WriteFile() call in nl_sock_transact_multiple__() has not been touched
since it is not needed yet.

Main motive for this change is to be able to unblock the DP Dump workflow.

Signed-off-by: Nithin Raju <nithin@vmware.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Eitan Eliahu <eliahue@vmware.com>
Acked-by: Alin Gabriel Serdean <aserdean@cloudbasesolutions.com>
---
 lib/netlink-socket.c | 46 +++++++++++++++++++++++++-------------------
 1 file changed, 26 insertions(+), 20 deletions(-)

diff --git a/lib/netlink-socket.c b/lib/netlink-socket.c
index 4d9832f48..a6be1861e 100644
--- a/lib/netlink-socket.c
+++ b/lib/netlink-socket.c
@@ -426,17 +426,20 @@ nl_sock_send__(struct nl_sock *sock, const struct ofpbuf *msg,
     do {
         int retval;
 #ifdef _WIN32
-        bool result;
-        DWORD last_error = 0;
-        result = WriteFile(sock->handle, ofpbuf_data(msg), ofpbuf_size(msg),
-                           &retval, NULL);
-        last_error = GetLastError();
-        if (last_error != ERROR_SUCCESS && !result) {
+        DWORD bytes;
+
+        if (!DeviceIoControl(sock->handle, OVS_IOCTL_WRITE,
+                            ofpbuf_data(msg), ofpbuf_size(msg), NULL, 0,
+                            &bytes, NULL)) {
             retval = -1;
-            errno = EAGAIN;
+            /* XXX: Map to a more appropriate error based on GetLastError(). */
+            errno = EINVAL;
+        } else {
+            retval = ofpbuf_size(msg);
         }
 #else
-        retval = send(sock->fd, ofpbuf_data(msg), ofpbuf_size(msg), wait ? 0 : MSG_DONTWAIT);
+        retval = send(sock->fd, ofpbuf_data(msg), ofpbuf_size(msg),
+                      wait ? 0 : MSG_DONTWAIT);
 #endif
         error = retval < 0 ? errno : 0;
     } while (error == EINTR);
@@ -488,12 +491,7 @@ nl_sock_recv__(struct nl_sock *sock, struct ofpbuf *buf, bool wait)
      * 'tail' to allow Netlink messages to be up to 64 kB long (a reasonable
      * figure since that's the maximum length of a Netlink attribute). */
     struct nlmsghdr *nlmsghdr;
-#ifdef _WIN32
-#define MAX_STACK_LENGTH 81920
-    uint8_t tail[MAX_STACK_LENGTH];
-#else
     uint8_t tail[65536];
-#endif
     struct iovec iov[2];
     struct msghdr msg;
     ssize_t retval;
@@ -522,15 +520,23 @@ nl_sock_recv__(struct nl_sock *sock, struct ofpbuf *buf, bool wait)
     do {
         nlmsghdr->nlmsg_len = UINT32_MAX;
 #ifdef _WIN32
-        boolean result = false;
-        DWORD last_error = 0;
-        result = ReadFile(sock->handle, tail, MAX_STACK_LENGTH, &retval, NULL);
-        last_error = GetLastError();
-        if (last_error != ERROR_SUCCESS && !result) {
+        DWORD bytes;
+        if (!DeviceIoControl(sock->handle, OVS_IOCTL_READ,
+                             NULL, 0, tail, sizeof tail, &bytes, NULL)) {
             retval = -1;
-            errno = EAGAIN;
+            errno = EINVAL;
         } else {
-            ofpbuf_put(buf, tail, retval);
+            retval = bytes;
+            if (retval == 0) {
+                retval = -1;
+                errno = EAGAIN;
+            } else {
+                if (retval >= buf->allocated) {
+                    ofpbuf_reinit(buf, retval);
+                }
+                memcpy(ofpbuf_data(buf), tail, retval);
+                ofpbuf_set_size(buf, retval);
+            }
         }
 #else
         retval = recvmsg(sock->fd, &msg, wait ? 0 : MSG_DONTWAIT);
-- 
2.20.1