1 files changed, 81 insertions, 0 deletions
diff --git a/ports/winnt/libntp/win32_io.c b/ports/winnt/libntp/win32_io.c
new file mode 100644
index 000000000000..9e7a86179853
--- /dev/null
+++ b/ports/winnt/libntp/win32_io.c
@@ -0,0 +1,81 @@
+/* This file implements i/o calls that are specific to Windows */
+
+#include <config.h>
+#include <stdio.h>
+#include "ntp_fp.h"
+#include "ntp_net.h"
+#include "ntp_stdlib.h"
+#include "ntp_syslog.h"
+#include "win32_io.h"
+#include <isc/win32os.h>
+
+/*
+ * Define this macro to control the behavior of connection
+ * resets on UDP sockets.  See Microsoft KnowledgeBase Article Q263823
+ * for details.
+ * Based on that article, it is surprising that a much newer winsock2.h
+ * does not define SIO_UDP_CONNRESET (the one that comes with VS 2008).
+ * NOTE: This requires that Windows 2000 systems install Service Pack 2
+ * or later.
+ */
+#ifndef SIO_UDP_CONNRESET 
+#define SIO_UDP_CONNRESET _WSAIOW(IOC_VENDOR,12) 
+#endif
+
+void
+InitSockets(
+	void
+	)
+{
+	WORD wVersionRequested;
+	WSADATA wsaData;
+	int err;
+
+	/* Need Winsock 2.0 or better */
+	wVersionRequested = MAKEWORD(2, 0);
+ 
+	err = WSAStartup(wVersionRequested, &wsaData);
+	if ( err != 0 ) {
+		SetLastError(err);
+		mfprintf(stderr, "No usable winsock: %m\n");
+		SetLastError(err);
+		msyslog(LOG_ERR, "No usable winsock: %m");
+		exit(1);
+	}
+}
+
+/*
+ * Windows 2000 systems incorrectly cause UDP sockets using WASRecvFrom
+ * to not work correctly, returning a WSACONNRESET error when a WSASendTo
+ * fails with an "ICMP port unreachable" response and preventing the
+ * socket from using the WSARecvFrom in subsequent operations.
+ * The function below fixes this, but requires that Windows 2000
+ * Service Pack 2 or later be installed on the system.  NT 4.0
+ * systems are not affected by this and work correctly.
+ * See Microsoft Knowledge Base Article Q263823 for details of this.
+ */
+void
+connection_reset_fix(
+	SOCKET		fd,
+	sockaddr_u *	addr
+	)
+{
+	DWORD dw;
+	BOOL  bNewBehavior = FALSE;
+	DWORD status;
+
+	/*
+	 * disable bad behavior using IOCTL: SIO_UDP_CONNRESET
+	 * NT 4.0 has no problem
+	 */
+	if (isc_win32os_majorversion() >= 5) {
+		status = WSAIoctl(fd, SIO_UDP_CONNRESET, &bNewBehavior,
+				  sizeof(bNewBehavior), NULL, 0,
+				  &dw, NULL, NULL);
+		if (SOCKET_ERROR == status)
+			msyslog(LOG_ERR,
+				"connection_reset_fix() failed for address %s: %m", 
+				stoa(addr));
+	}
+}
+