bpo-29883: Asyncio proactor udp (GH-13440)

Follow-up for #1067


https://bugs.python.org/issue29883

1 files changed, 356 insertions, 16 deletions

diff --git a/Modules/overlapped.c b/Modules/overlapped.c
index e5a209b..aad531e 100644
--- a/Modules/overlapped.c
+++ b/Modules/overlapped.c
@@ -39,7 +39,8 @@
 
 enum {TYPE_NONE, TYPE_NOT_STARTED, TYPE_READ, TYPE_READINTO, TYPE_WRITE,
       TYPE_ACCEPT, TYPE_CONNECT, TYPE_DISCONNECT, TYPE_CONNECT_NAMED_PIPE,
-      TYPE_WAIT_NAMED_PIPE_AND_CONNECT, TYPE_TRANSMIT_FILE};
+      TYPE_WAIT_NAMED_PIPE_AND_CONNECT, TYPE_TRANSMIT_FILE, TYPE_READ_FROM,
+      TYPE_WRITE_TO};
 
 typedef struct {
     PyObject_HEAD
@@ -53,8 +54,19 @@ typedef struct {
     union {
         /* Buffer allocated by us: TYPE_READ and TYPE_ACCEPT */
         PyObject *allocated_buffer;
-        /* Buffer passed by the user: TYPE_WRITE and TYPE_READINTO */
+        /* Buffer passed by the user: TYPE_WRITE, TYPE_WRITE_TO, and TYPE_READINTO */
         Py_buffer user_buffer;
+
+        /* Data used for reading from a connectionless socket:
+           TYPE_READ_FROM */
+        struct {
+            // A (buffer, (host, port)) tuple
+            PyObject *result;
+            // The actual read buffer
+            PyObject *allocated_buffer;
+            struct sockaddr_in6 address;
+            int address_length;
+        } read_from;
     };
 } OverlappedObject;
 
@@ -570,16 +582,32 @@ static int
 Overlapped_clear(OverlappedObject *self)
 {
     switch (self->type) {
-    case TYPE_READ:
-    case TYPE_ACCEPT:
-        Py_CLEAR(self->allocated_buffer);
-        break;
-    case TYPE_WRITE:
-    case TYPE_READINTO:
-        if (self->user_buffer.obj) {
-            PyBuffer_Release(&self->user_buffer);
+        case TYPE_READ:
+        case TYPE_ACCEPT: {
+            Py_CLEAR(self->allocated_buffer);
+            break;
+        }
+        case TYPE_READ_FROM: {
+            // An initial call to WSARecvFrom will only allocate the buffer.
+            // The result tuple of (message, address) is only
+            // allocated _after_ a message has been received.
+            if(self->read_from.result) {
+                // We've received a message, free the result tuple.
+                Py_CLEAR(self->read_from.result);
+            }
+            if(self->read_from.allocated_buffer) {
+                Py_CLEAR(self->read_from.allocated_buffer);
+            }
+            break;
+        }
+        case TYPE_WRITE:
+        case TYPE_WRITE_TO:
+        case TYPE_READINTO: {
+            if (self->user_buffer.obj) {
+                PyBuffer_Release(&self->user_buffer);
+            }
+            break;
         }
-        break;
     }
     self->type = TYPE_NOT_STARTED;
     return 0;
@@ -627,6 +655,73 @@ Overlapped_dealloc(OverlappedObject *self)
     SetLastError(olderr);
 }
 
+
+/* Convert IPv4 sockaddr to a Python str. */
+
+static PyObject *
+make_ipv4_addr(const struct sockaddr_in *addr)
+{
+        char buf[INET_ADDRSTRLEN];
+        if (inet_ntop(AF_INET, &addr->sin_addr, buf, sizeof(buf)) == NULL) {
+                PyErr_SetFromErrno(PyExc_OSError);
+                return NULL;
+        }
+        return PyUnicode_FromString(buf);
+}
+
+#ifdef ENABLE_IPV6
+/* Convert IPv6 sockaddr to a Python str. */
+
+static PyObject *
+make_ipv6_addr(const struct sockaddr_in6 *addr)
+{
+        char buf[INET6_ADDRSTRLEN];
+        if (inet_ntop(AF_INET6, &addr->sin6_addr, buf, sizeof(buf)) == NULL) {
+                PyErr_SetFromErrno(PyExc_OSError);
+                return NULL;
+        }
+        return PyUnicode_FromString(buf);
+}
+#endif
+
+static PyObject*
+unparse_address(LPSOCKADDR Address, DWORD Length)
+{
+        /* The function is adopted from mocketmodule.c makesockaddr()*/
+
+    switch(Address->sa_family) {
+        case AF_INET: {
+            const struct sockaddr_in *a = (const struct sockaddr_in *)Address;
+            PyObject *addrobj = make_ipv4_addr(a);
+            PyObject *ret = NULL;
+            if (addrobj) {
+                ret = Py_BuildValue("Oi", addrobj, ntohs(a->sin_port));
+                Py_DECREF(addrobj);
+            }
+            return ret;
+        }
+#ifdef ENABLE_IPV6
+        case AF_INET6: {
+            const struct sockaddr_in6 *a = (const struct sockaddr_in6 *)Address;
+            PyObject *addrobj = make_ipv6_addr(a);
+            PyObject *ret = NULL;
+            if (addrobj) {
+                ret = Py_BuildValue("OiII",
+                                    addrobj,
+                                    ntohs(a->sin6_port),
+                                    ntohl(a->sin6_flowinfo),
+                                    a->sin6_scope_id);
+                Py_DECREF(addrobj);
+            }
+            return ret;
+        }
+#endif /* ENABLE_IPV6 */
+        default: {
+            return SetFromWindowsErr(ERROR_INVALID_PARAMETER);
+        }
+    }
+}
+
 PyDoc_STRVAR(
     Overlapped_cancel_doc,
     "cancel() -> None\n\n"
@@ -670,6 +765,7 @@ Overlapped_getresult(OverlappedObject *self, PyObject *args)
     DWORD transferred = 0;
     BOOL ret;
     DWORD err;
+    PyObject *addr;
 
     if (!PyArg_ParseTuple(args, "|" F_BOOL, &wait))
         return NULL;
@@ -695,8 +791,15 @@ Overlapped_getresult(OverlappedObject *self, PyObject *args)
         case ERROR_MORE_DATA:
             break;
         case ERROR_BROKEN_PIPE:
-            if (self->type == TYPE_READ || self->type == TYPE_READINTO)
+            if (self->type == TYPE_READ || self->type == TYPE_READINTO) {
                 break;
+            }
+            else if (self->type == TYPE_READ_FROM &&
+                     (self->read_from.result != NULL ||
+                      self->read_from.allocated_buffer != NULL))
+            {
+                break;
+            }
             /* fall through */
         default:
             return SetFromWindowsErr(err);
@@ -708,8 +811,43 @@ Overlapped_getresult(OverlappedObject *self, PyObject *args)
             if (transferred != PyBytes_GET_SIZE(self->allocated_buffer) &&
                 _PyBytes_Resize(&self->allocated_buffer, transferred))
                 return NULL;
+
             Py_INCREF(self->allocated_buffer);
             return self->allocated_buffer;
+        case TYPE_READ_FROM:
+            assert(PyBytes_CheckExact(self->read_from.allocated_buffer));
+
+            if (transferred != PyBytes_GET_SIZE(
+                    self->read_from.allocated_buffer) &&
+                _PyBytes_Resize(&self->read_from.allocated_buffer, transferred))
+            {
+                return NULL;
+            }
+
+            // unparse the address
+            addr = unparse_address((SOCKADDR*)&self->read_from.address,
+                                   self->read_from.address_length);
+
+            if (addr == NULL) {
+                return NULL;
+            }
+
+            // The result is a two item tuple: (message, address)
+            self->read_from.result = PyTuple_New(2);
+            if (self->read_from.result == NULL) {
+                Py_CLEAR(addr);
+                return NULL;
+            }
+
+            // first item: message
+            Py_INCREF(self->read_from.allocated_buffer);
+            PyTuple_SET_ITEM(self->read_from.result, 0,
+                             self->read_from.allocated_buffer);
+            // second item: address
+            PyTuple_SET_ITEM(self->read_from.result, 1, addr);
+
+            Py_INCREF(self->read_from.result);
+            return self->read_from.result;
         default:
             return PyLong_FromUnsignedLong((unsigned long) transferred);
     }
@@ -1121,7 +1259,6 @@ parse_address(PyObject *obj, SOCKADDR *Address, int Length)
     return -1;
 }
 
-
 PyDoc_STRVAR(
     Overlapped_ConnectEx_doc,
     "ConnectEx(client_handle, address_as_bytes) -> Overlapped[None]\n\n"
@@ -1314,7 +1451,7 @@ PyDoc_STRVAR(
     "Connect to the pipe for asynchronous I/O (overlapped).");
 
 static PyObject *
-ConnectPipe(OverlappedObject *self, PyObject *args)
+overlapped_ConnectPipe(PyObject *self, PyObject *args)
 {
     PyObject *AddressObj;
     wchar_t *Address;
@@ -1362,15 +1499,213 @@ Overlapped_traverse(OverlappedObject *self, visitproc visit, void *arg)
         Py_VISIT(self->allocated_buffer);
         break;
     case TYPE_WRITE:
+    case TYPE_WRITE_TO:
     case TYPE_READINTO:
         if (self->user_buffer.obj) {
             Py_VISIT(&self->user_buffer.obj);
         }
         break;
+    case TYPE_READ_FROM:
+        if(self->read_from.result) {
+            Py_VISIT(self->read_from.result);
+        }
+        if(self->read_from.allocated_buffer) {
+            Py_VISIT(self->read_from.allocated_buffer);
+        }
     }
     return 0;
 }
 
+// UDP functions
+
+PyDoc_STRVAR(
+    WSAConnect_doc,
+    "WSAConnect(client_handle, address_as_bytes) -> Overlapped[None]\n\n"
+    "Bind a remote address to a connectionless (UDP) socket");
+
+/*
+ * Note: WSAConnect does not support Overlapped I/O so this function should
+ * _only_ be used for connectionless sockets (UDP).
+ */
+static PyObject *
+overlapped_WSAConnect(PyObject *self, PyObject *args)
+{
+    SOCKET ConnectSocket;
+    PyObject *AddressObj;
+    char AddressBuf[sizeof(struct sockaddr_in6)];
+    SOCKADDR *Address = (SOCKADDR*)AddressBuf;
+    int Length;
+    int err;
+
+    if (!PyArg_ParseTuple(args, F_HANDLE "O", &ConnectSocket, &AddressObj)) {
+        return NULL;
+    }
+
+    Length = sizeof(AddressBuf);
+    Length = parse_address(AddressObj, Address, Length);
+    if (Length < 0) {
+        return NULL;
+    }
+
+    Py_BEGIN_ALLOW_THREADS
+    // WSAConnect does not support overlapped I/O so this call will
+    // successfully complete immediately.
+    err = WSAConnect(ConnectSocket, Address, Length,
+                        NULL, NULL, NULL, NULL);
+    Py_END_ALLOW_THREADS
+
+    if (err == 0) {
+        Py_RETURN_NONE;
+    }
+    else {
+        return SetFromWindowsErr(WSAGetLastError());
+    }
+}
+
+PyDoc_STRVAR(
+    Overlapped_WSASendTo_doc,
+    "WSASendTo(handle, buf, flags, address_as_bytes) -> "
+    "Overlapped[bytes_transferred]\n\n"
+    "Start overlapped sendto over a connectionless (UDP) socket");
+
+static PyObject *
+Overlapped_WSASendTo(OverlappedObject *self, PyObject *args)
+{
+    HANDLE handle;
+    PyObject *bufobj;
+    DWORD flags;
+    PyObject *AddressObj;
+    char AddressBuf[sizeof(struct sockaddr_in6)];
+    SOCKADDR *Address = (SOCKADDR*)AddressBuf;
+    int AddressLength;
+    DWORD written;
+    WSABUF wsabuf;
+    int ret;
+    DWORD err;
+
+    if (!PyArg_ParseTuple(args, F_HANDLE "O" F_DWORD "O",
+                          &handle, &bufobj, &flags, &AddressObj))
+    {
+        return NULL;
+    }
+
+    // Parse the "to" address
+    AddressLength = sizeof(AddressBuf);
+    AddressLength = parse_address(AddressObj, Address, AddressLength);
+    if (AddressLength < 0) {
+        return NULL;
+    }
+
+    if (self->type != TYPE_NONE) {
+        PyErr_SetString(PyExc_ValueError, "operation already attempted");
+        return NULL;
+    }
+
+    if (!PyArg_Parse(bufobj, "y*", &self->user_buffer)) {
+        return NULL;
+    }
+
+#if SIZEOF_SIZE_T > SIZEOF_LONG
+    if (self->user_buffer.len > (Py_ssize_t)ULONG_MAX) {
+        PyBuffer_Release(&self->user_buffer);
+        PyErr_SetString(PyExc_ValueError, "buffer too large");
+        return NULL;
+    }
+#endif
+
+    self->type = TYPE_WRITE_TO;
+    self->handle = handle;
+    wsabuf.len = (DWORD)self->user_buffer.len;
+    wsabuf.buf = self->user_buffer.buf;
+
+    Py_BEGIN_ALLOW_THREADS
+    ret = WSASendTo((SOCKET)handle, &wsabuf, 1, &written, flags,
+                    Address, AddressLength, &self->overlapped, NULL);
+    Py_END_ALLOW_THREADS
+
+    self->error = err = (ret == SOCKET_ERROR ? WSAGetLastError() :
+                                               ERROR_SUCCESS);
+
+    switch(err) {
+        case ERROR_SUCCESS:
+        case ERROR_IO_PENDING:
+            Py_RETURN_NONE;
+        default:
+            self->type = TYPE_NOT_STARTED;
+            return SetFromWindowsErr(err);
+    }
+}
+
+
+
+PyDoc_STRVAR(
+    Overlapped_WSARecvFrom_doc,
+    "RecvFile(handle, size, flags) -> Overlapped[(message, (host, port))]\n\n"
+    "Start overlapped receive");
+
+static PyObject *
+Overlapped_WSARecvFrom(OverlappedObject *self, PyObject *args)
+{
+    HANDLE handle;
+    DWORD size;
+    DWORD flags = 0;
+    DWORD nread;
+    PyObject *buf;
+    WSABUF wsabuf;
+    int ret;
+    DWORD err;
+
+    if (!PyArg_ParseTuple(args, F_HANDLE F_DWORD "|" F_DWORD,
+                          &handle, &size, &flags))
+    {
+        return NULL;
+    }
+
+    if (self->type != TYPE_NONE) {
+        PyErr_SetString(PyExc_ValueError, "operation already attempted");
+        return NULL;
+    }
+
+#if SIZEOF_SIZE_T <= SIZEOF_LONG
+    size = Py_MIN(size, (DWORD)PY_SSIZE_T_MAX);
+#endif
+    buf = PyBytes_FromStringAndSize(NULL, Py_MAX(size, 1));
+    if (buf == NULL) {
+        return NULL;
+    }
+
+    wsabuf.len = size;
+    wsabuf.buf = PyBytes_AS_STRING(buf);
+
+    self->type = TYPE_READ_FROM;
+    self->handle = handle;
+    self->read_from.allocated_buffer = buf;
+    memset(&self->read_from.address, 0, sizeof(self->read_from.address));
+    self->read_from.address_length = sizeof(self->read_from.address);
+
+    Py_BEGIN_ALLOW_THREADS
+    ret = WSARecvFrom((SOCKET)handle, &wsabuf, 1, &nread, &flags,
+                      (SOCKADDR*)&self->read_from.address,
+                      &self->read_from.address_length,
+                      &self->overlapped, NULL);
+    Py_END_ALLOW_THREADS
+
+    self->error = err = (ret < 0 ? WSAGetLastError() : ERROR_SUCCESS);
+
+    switch(err) {
+    case ERROR_BROKEN_PIPE:
+        mark_as_completed(&self->overlapped);
+        return SetFromWindowsErr(err);
+    case ERROR_SUCCESS:
+    case ERROR_MORE_DATA:
+    case ERROR_IO_PENDING:
+        Py_RETURN_NONE;
+    default:
+        self->type = TYPE_NOT_STARTED;
+        return SetFromWindowsErr(err);
+    }
+}
+
 
 static PyMethodDef Overlapped_methods[] = {
     {"getresult", (PyCFunction) Overlapped_getresult,
@@ -1399,6 +1734,10 @@ static PyMethodDef Overlapped_methods[] = {
      METH_VARARGS, Overlapped_TransmitFile_doc},
     {"ConnectNamedPipe", (PyCFunction) Overlapped_ConnectNamedPipe,
      METH_VARARGS, Overlapped_ConnectNamedPipe_doc},
+    {"WSARecvFrom", (PyCFunction) Overlapped_WSARecvFrom,
+     METH_VARARGS, Overlapped_WSARecvFrom_doc },
+    {"WSASendTo", (PyCFunction) Overlapped_WSASendTo,
+     METH_VARARGS, Overlapped_WSASendTo_doc },
     {NULL}
 };
 
@@ -1484,9 +1823,10 @@ static PyMethodDef overlapped_functions[] = {
      METH_VARARGS, SetEvent_doc},
     {"ResetEvent", overlapped_ResetEvent,
      METH_VARARGS, ResetEvent_doc},
-    {"ConnectPipe",
-     (PyCFunction) ConnectPipe,
+    {"ConnectPipe", overlapped_ConnectPipe,
      METH_VARARGS, ConnectPipe_doc},
+    {"WSAConnect", overlapped_WSAConnect,
+     METH_VARARGS, WSAConnect_doc},
     {NULL}
 };