[ovs-dev] [PATCH v1] Windows NetLink Socket - Support for asynchronous event notification
Eitan Eliahu
eliahue at vmware.com
Thu Sep 4 10:23:59 UTC 2014
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 n the NL socket. The thread will read all all event
messages synchronous through the call of nl_sock_recv()
Signed-off-by: Eitan Eliahu eliahue at vmware.com
---
datapath-windows/include/OvsDpInterfaceExt.h | 1 +
lib/netlink-socket.c | 82 ++++++++++++++++++++++++++--
2 files changed, 79 insertions(+), 4 deletions(-)
diff --git a/datapath-windows/include/OvsDpInterfaceExt.h b/datapath-windows/include/OvsDpInterfaceExt.h
index 73dfcbe..ab2088a 100644
--- 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..4b535f0 100644
--- 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
@@ -139,21 +140,30 @@ nl_sock_create(int protocol, struct nl_sock **sockp)
sock = xmalloc(sizeof *sock);
#ifdef _WIN32
- sock->handle = CreateFileA("\\\\.\\OpenVSwitchDevice",
+ sock->handle = CreateFile(TEXT("\\\\.\\OpenVSwitchDevice"),
GENERIC_READ | GENERIC_WRITE,
FILE_SHARE_READ | FILE_SHARE_WRITE,
NULL, OPEN_EXISTING,
- FILE_ATTRIBUTE_NORMAL, NULL);
-
- int last_error = GetLastError();
+ 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) {
+ int last_error = GetLastError();
VLOG_ERR("fcntl: %s", ovs_strerror(errno));
goto error;
}
@@ -221,6 +231,9 @@ error:
}
}
#ifdef _WIN32
+ if (sock->overlapped.hEvent) {
+ CloseHandle(sock->overlapped.hEvent);
+ }
if (sock->handle != INVALID_HANDLE_VALUE) {
CloseHandle(sock->handle);
}
@@ -248,6 +261,9 @@ 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 +1056,70 @@ 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 assocaited 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);
--
1.9.4.msysgit.0
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