Re: [Qemu-devel][PATCH] Tap and VLAN socket support for win32

["Kazu" <kazoo@r3.dion.ne.jp>]

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Sunday, February 05, 2006 3:28 AM Fabrice  Bellard wrote:
> Kazu wrote:
>> Thursday, February 02, 2006 8:10 AM Fabrice Bellard wrote:
>>
>>> Hi,
>>>
>>> I merged your patches and I made important changes to simplify them. I
>>> did not do any tests so tell me if you see problems.
>>>
>>
>> -net socket,connect doesn't work. On Windows host, connect returns with
>> err
>> = WSAEWOULDBLOCK and second time err = WSAEINVAL. I think changing the
>> place
>> of EWOULDBLOCK would be good. On Linux host, EWOULDBLOCK is the same as
>> EAGAIN but a patch works on both Linux and Windows.
>
> Unfortunately on Linux the correct return value we are expecting is
> EINPROGRESS. EAGAIN means that the 'connect' was not initiated so it is
> necessary to redo it.
>

There is not good way to detect a completion of asynchronous connect. So I
used an event object to detect it. A patch is attached.

>>
>> For -net socket,mcast, bind have to be done by sin_addr.s_addr =
>> INADDR_ANY.
>> It seems that it works on Linux host.
>
> It works on Linux but it is not correct because it prevents from listening
> to several multicast addresses at the same time. If doing the same on
> Windows is not possible I agree to make a special case.
>

I couldn't find a way to set a multicast address. I made it a special case
in the patch

Regard,
Kazu

Index: vl.c
===================================================================
RCS file: /sources/qemu/qemu/vl.c,v
retrieving revision 1.162
diff -u -r1.162 vl.c
--- vl.c 5 Feb 2006 04:14:41 -0000 1.162
+++ vl.c 8 Feb 2006 05:50:28 -0000
@@ -1083,9 +1083,10 @@

 #define socket_error() WSAGetLastError()
 #undef EINTR
-#define EWOULDBLOCK WSAEWOULDBLOCK
-#define EINTR       WSAEINTR
-#define EINPROGRESS WSAEINPROGRESS
+#define EWOULDBLOCK   WSAEWOULDBLOCK
+#define EINTR         WSAEINTR
+#define EINPROGRESS   WSAEINPROGRESS
+#define EADDRNOTAVAIL WSAEADDRNOTAVAIL

 static void socket_cleanup(void)
 {
@@ -1136,6 +1137,59 @@
     ioctlsocket(fd, FIONBIO, &opt);
 }

+static int socket_set_event(SOCKET fd, WSAEVENT *phEvent)
+{
+    int ret;
+
+    *phEvent = WSACreateEvent();
+    if (*phEvent == WSA_INVALID_EVENT) {
+        perror("connect: CreateEvent");
+        return -1;
+    }
+
+    ret = WSAEventSelect(fd, *phEvent, FD_CONNECT);
+    if (ret == SOCKET_ERROR) {
+        perror("connect: EventSelect");
+        return -1;
+    }
+    return 0;
+}
+
+static int socket_wait_event(SOCKET fd, WSAEVENT *phEvent)
+{
+    WSANETWORKEVENTS events;
+    int ret;
+
+    ret = WSAWaitForMultipleEvents(1, phEvent, FALSE, WSA_INFINITE, FALSE);
+    if (ret == WSA_WAIT_FAILED) {
+        perror("connect: Wait");
+        goto fail;
+    }
+
+    ret = WSAEnumNetworkEvents(fd, *phEvent, &events);
+    if (ret == SOCKET_ERROR) {
+        perror("connect: EnumEvent");
+        goto fail;
+    } else {
+        if (events.lNetworkEvents & FD_CONNECT) {
+            if (events.iErrorCode[FD_CONNECT_BIT] == 0) {
+                if (*phEvent != WSA_INVALID_EVENT)
+                    WSACloseEvent(*phEvent);
+                return 1;
+            } else {
+                perror("connect: refused");
+                goto fail;
+            }
+        } else {
+            perror("connect: fd_connect");
+            goto fail;
+        }
+    }
+ fail:
+    if (*phEvent != WSA_INVALID_EVENT)
+        WSACloseEvent(*phEvent);
+    return 0;
+}
 #else

 #define socket_error() errno
@@ -2330,7 +2384,9 @@
 {
     struct ip_mreq imr;
     int fd;
-    int val, ret;
+    int val, ret, err;
+    struct sockaddr_in addr;
+
     if (!IN_MULTICAST(ntohl(mcastaddr->sin_addr.s_addr))) {
  fprintf(stderr, "qemu: error: specified mcastaddr \"%s\" (0x%08x) does not
contain a multicast address\n",
   inet_ntoa(mcastaddr->sin_addr),
@@ -2354,8 +2410,22 @@

     ret = bind(fd, (struct sockaddr *)mcastaddr, sizeof(*mcastaddr));
     if (ret < 0) {
-        perror("bind");
-        goto fail;
+        err = socket_error();
+        if (err == EADDRNOTAVAIL) {
+            memset(&addr, 0, sizeof(addr));
+            addr.sin_family = AF_INET;
+            addr.sin_port = mcastaddr->sin_port;
+            addr.sin_addr.s_addr = INADDR_ANY;
+
+            ret = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
+            if (ret < 0) {
+                perror("bind");
+                goto fail;
+            }
+        } else {
+            perror("bind");
+            goto fail;
+        }
     }

     /* Add host to multicast group */
@@ -2557,11 +2627,15 @@
     return 0;
 }

+
 static int net_socket_connect_init(VLANState *vlan, const char *host_str)
 {
     NetSocketState *s;
     int fd, connected, ret, err;
     struct sockaddr_in saddr;
+#ifdef _WIN32
+    WSAEVENT hEvent;
+#endif

     if (parse_host_port(&saddr, host_str) < 0)
         return -1;
@@ -2573,6 +2647,26 @@
     }
     socket_set_nonblock(fd);

+#ifdef _WIN32
+    ret = socket_set_event(fd, &hEvent);
+    if (ret < 0) {
+        perror("connect: set_event");
+        closesocket(fd);
+        return -1;
+    }
+
+    connected = 0;
+    ret = connect(fd, (struct sockaddr *)&saddr, sizeof(saddr));
+
+    err = socket_wait_event(fd, &hEvent);
+    if (err > 0) {
+        connected = 1;
+    } else {
+        perror("connect");
+        closesocket(fd);
+        return -1;
+    }
+#else
     connected = 0;
     for(;;) {
         ret = connect(fd, (struct sockaddr *)&saddr, sizeof(saddr));
@@ -2591,6 +2685,8 @@
             break;
         }
     }
+#endif
+
     s = net_socket_fd_init(vlan, fd, connected);
     if (!s)
         return -1;


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