netlink-socket: Add support for async notification on Windows.

We keep an outstanding, out of band, I/O request in the driver at all time.
Once an event generated the driver queues the event message, completes the
pending I/O and unblocks the calling thread through setting the event in the
overlapped structure in the NL socket. The thread will read all all event
messages synchronously through the call of nl_sock_recv()

Signed-off-by: Eitan Eliahu <eliahue@vmware.com>
Acked-by: Samuel Ghinet <sghinet@cloudbasesolutions.com>
Acked-by: Ankur Sharma <ankursharma@vmware.com>
Acked-by: Alin Gabriel Serdean <aserdean at cloudbasesolutions.com>
Acked-by: Saurabh Shah <ssaurabh@vmware.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>

diff --git a/datapath-windows/include/OvsDpInterfaceExt.h b/datapath-windows/include/OvsDpInterfaceExt.h
index 73dfcbe..ab2088a 100644 (file)
--- a/datapath-windows/include/OvsDpInterfaceExt.h
+++ b/datapath-windows/include/OvsDpInterfaceExt.h
@@ -70,6 +70,7 @@
 /* Commands available under the OVS_WIN_CONTROL_FAMILY. */
 enum ovs_win_control_cmd {
     OVS_CTRL_CMD_WIN_GET_PID,
+    OVS_CTRL_CMD_WIN_PEND_REQ
 };
 
 #endif /* __OVS_DP_INTERFACE_EXT_H_ */

diff --git a/lib/netlink-socket.c b/lib/netlink-socket.c
index a6be186..f91b909 100644 (file)
--- a/lib/netlink-socket.c
+++ b/lib/netlink-socket.c
@@ -80,6 +80,7 @@ static int get_sock_pid_from_kernel(struct nl_sock *sock);
 struct nl_sock {
 #ifdef _WIN32
     HANDLE handle;
+    OVERLAPPED overlapped;
 #else
     int fd;
 #endif
@@ -139,18 +140,26 @@ nl_sock_create(int protocol, struct nl_sock **sockp)
     sock = xmalloc(sizeof *sock);
 
 #ifdef _WIN32
-    sock->handle = CreateFileA("\\\\.\\OpenVSwitchDevice",
-                               GENERIC_READ | GENERIC_WRITE,
-                               FILE_SHARE_READ | FILE_SHARE_WRITE,
-                               NULL, OPEN_EXISTING,
-                               FILE_ATTRIBUTE_NORMAL, NULL);
-
-    int last_error = GetLastError();
+    sock->handle = CreateFile(OVS_DEVICE_NAME_USER,
+                              GENERIC_READ | GENERIC_WRITE,
+                              FILE_SHARE_READ | FILE_SHARE_WRITE,
+                              NULL, OPEN_EXISTING,
+                              FILE_FLAG_OVERLAPPED, NULL);
 
     if (sock->handle == INVALID_HANDLE_VALUE) {
+        int last_error = GetLastError();
+        VLOG_ERR("fcntl: %s", ovs_strerror(last_error));
+        goto error;
+    }
+
+    memset(&sock->overlapped, 0, sizeof sock->overlapped);
+    sock->overlapped.hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
+    if (sock->overlapped.hEvent == NULL) {
+        int last_error = GetLastError();
         VLOG_ERR("fcntl: %s", ovs_strerror(last_error));
         goto error;
     }
+
 #else
     sock->fd = socket(AF_NETLINK, SOCK_RAW, protocol);
     if (sock->fd < 0) {
@@ -221,6 +230,9 @@ error:
         }
     }
 #ifdef _WIN32
+    if (sock->overlapped.hEvent) {
+        CloseHandle(sock->overlapped.hEvent);
+    }
     if (sock->handle != INVALID_HANDLE_VALUE) {
         CloseHandle(sock->handle);
     }
@@ -248,6 +260,9 @@ nl_sock_destroy(struct nl_sock *sock)
 {
     if (sock) {
 #ifdef _WIN32
+        if (sock->overlapped.hEvent) {
+            CloseHandle(sock->overlapped.hEvent);
+        }
         CloseHandle(sock->handle);
 #else
         close(sock->fd);
@@ -1040,12 +1055,69 @@ nl_dump_done(struct nl_dump *dump)
     return status == EOF ? 0 : status;
 }
 
+#ifdef _WIN32
+/* Pend an I/O request in the driver. The driver completes the I/O whenever
+ * an event or a packet is ready to be read. Once the I/O is completed
+ * the overlapped structure event associated with the pending I/O will be set
+ */
+static int
+pend_io_request(const struct nl_sock *sock)
+{
+    struct ofpbuf request;
+    uint64_t request_stub[128];
+    struct ovs_header *ovs_header;
+    struct nlmsghdr *nlmsg;
+    uint32_t seq;
+    int retval;
+    int error;
+    DWORD bytes;
+    OVERLAPPED *overlapped = &sock->overlapped;
+
+    int ovs_msg_size = sizeof (struct nlmsghdr) + sizeof (struct genlmsghdr) +
+                               sizeof (struct ovs_header);
+
+    ofpbuf_use_stub(&request, request_stub, sizeof request_stub);
+
+    seq = nl_sock_allocate_seq(sock, 1);
+    nl_msg_put_genlmsghdr(&request, 0, OVS_WIN_NL_CTRL_FAMILY_ID, 0,
+                          OVS_CTRL_CMD_WIN_PEND_REQ, OVS_WIN_CONTROL_VERSION);
+    nlmsg = nl_msg_nlmsghdr(&request);
+    nlmsg->nlmsg_seq = seq;
+
+    ovs_header = ofpbuf_put_uninit(&request, sizeof *ovs_header);
+    ovs_header->dp_ifindex = 0;
+
+    if (!DeviceIoControl(sock->handle, OVS_IOCTL_WRITE,
+                         ofpbuf_data(&request), ofpbuf_size(&request),
+                         NULL, 0, &bytes, overlapped)) {
+        error = GetLastError();
+        /* Check if the I/O got pended */
+        if (error != ERROR_IO_INCOMPLETE && error != ERROR_IO_PENDING) {
+            VLOG_ERR("nl_sock_wait failed - %s\n", ovs_format_message(error));
+            retval = EINVAL;
+            goto done;
+        }
+    } else {
+        /* The I/O was completed synchronously */
+        poll_immediate_wake();
+    }
+    retval = 0;
+
+done:
+    ofpbuf_uninit(&request);
+    return retval;
+}
+#endif  /* _WIN32 */
+
 /* Causes poll_block() to wake up when any of the specified 'events' (which is
  * a OR'd combination of POLLIN, POLLOUT, etc.) occur on 'sock'. */
 void
 nl_sock_wait(const struct nl_sock *sock, short int events)
 {
 #ifdef _WIN32
+    if (sock->overlapped.Internal != STATUS_PENDING) {
+        pend_io_request(sock);
+    }
     poll_fd_wait(sock->handle, events);
 #else
     poll_fd_wait(sock->fd, events);