1 files changed, 62 insertions, 19 deletions

diff --git a/drivers/usb/net/rndis_host.c b/drivers/usb/net/rndis_host.c
index a322a16d9cf8..be888d2d813c 100644
--- a/drivers/usb/net/rndis_host.c
+++ b/drivers/usb/net/rndis_host.c
@@ -49,6 +49,8 @@
  *    - In some cases, MS-Windows will emit undocumented requests; this
  *      matters more to peripheral implementations than host ones.
  *
+ * Moreover there's a no-open-specs variant of RNDIS called "ActiveSync".
+ *
  * For these reasons and others, ** USE OF RNDIS IS STRONGLY DISCOURAGED ** in
  * favor of such non-proprietary alternatives as CDC Ethernet or the newer (and
  * currently rare) "Ethernet Emulation Model" (EEM).
@@ -61,6 +63,9 @@
  *  - control-in:  GET_ENCAPSULATED
  *
  * We'll try to ignore the RESPONSE_AVAILABLE notifications.
+ *
+ * REVISIT some RNDIS implementations seem to have curious issues still
+ * to be resolved.
  */
 struct rndis_msg_hdr {
         __le32  msg_type;                       /* RNDIS_MSG_* */
@@ -71,8 +76,14 @@ struct rndis_msg_hdr {
         // ... and more
 } __attribute__ ((packed));
 
-/* RNDIS defines this (absurdly huge) control timeout */
-#define RNDIS_CONTROL_TIMEOUT_MS        (10 * 1000)
+/* MS-Windows uses this strange size, but RNDIS spec says 1024 minimum */
+#define CONTROL_BUFFER_SIZE             1025
+
+/* RNDIS defines an (absurdly huge) 10 second control timeout,
+ * but ActiveSync seems to use a more usual 5 second timeout
+ * (which matches the USB 2.0 spec).
+ */
+#define RNDIS_CONTROL_TIMEOUT_MS        (5 * 1000)
 
 
 #define ccpu2 __constant_cpu_to_le32
@@ -270,6 +281,7 @@ static void rndis_status(struct usbnet *dev, struct urb *urb)
 static int rndis_command(struct usbnet *dev, struct rndis_msg_hdr *buf)
 {
         struct cdc_state        *info = (void *) &dev->data;
+        int                     master_ifnum;
         int                     retval;
         unsigned                count;
         __le32                  rsp;
@@ -279,7 +291,7 @@ static int rndis_command(struct usbnet *dev, struct rndis_msg_hdr *buf)
          * disconnect(): either serialize, or dispatch responses on xid
          */
 
-        /* Issue the request; don't bother byteswapping our xid */
+        /* Issue the request; xid is unique, don't bother byteswapping it */
         if (likely(buf->msg_type != RNDIS_MSG_HALT
                         && buf->msg_type != RNDIS_MSG_RESET)) {
                 xid = dev->xid++;
@@ -287,11 +299,12 @@ static int rndis_command(struct usbnet *dev, struct rndis_msg_hdr *buf)
                         xid = dev->xid++;
                 buf->request_id = (__force __le32) xid;
         }
+        master_ifnum = info->control->cur_altsetting->desc.bInterfaceNumber;
         retval = usb_control_msg(dev->udev,
                 usb_sndctrlpipe(dev->udev, 0),
                 USB_CDC_SEND_ENCAPSULATED_COMMAND,
                 USB_TYPE_CLASS | USB_RECIP_INTERFACE,
-                0, info->u->bMasterInterface0,
+                0, master_ifnum,
                 buf, le32_to_cpu(buf->msg_len),
                 RNDIS_CONTROL_TIMEOUT_MS);
         if (unlikely(retval < 0 || xid == 0))
@@ -306,13 +319,13 @@ static int rndis_command(struct usbnet *dev, struct rndis_msg_hdr *buf)
          */
         rsp = buf->msg_type | RNDIS_MSG_COMPLETION;
         for (count = 0; count < 10; count++) {
-                memset(buf, 0, 1024);
+                memset(buf, 0, CONTROL_BUFFER_SIZE);
                 retval = usb_control_msg(dev->udev,
                         usb_rcvctrlpipe(dev->udev, 0),
                         USB_CDC_GET_ENCAPSULATED_RESPONSE,
                         USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
-                        0, info->u->bMasterInterface0,
-                        buf, 1024,
+                        0, master_ifnum,
+                        buf, CONTROL_BUFFER_SIZE,
                         RNDIS_CONTROL_TIMEOUT_MS);
                 if (likely(retval >= 8)) {
                         msg_len = le32_to_cpu(buf->msg_len);
@@ -350,7 +363,7 @@ static int rndis_command(struct usbnet *dev, struct rndis_msg_hdr *buf)
                                         usb_sndctrlpipe(dev->udev, 0),
                                         USB_CDC_SEND_ENCAPSULATED_COMMAND,
                                         USB_TYPE_CLASS | USB_RECIP_INTERFACE,
-                                        0, info->u->bMasterInterface0,
+                                        0, master_ifnum,
                                         msg, sizeof *msg,
                                         RNDIS_CONTROL_TIMEOUT_MS);
                                 if (unlikely(retval < 0))
@@ -393,38 +406,64 @@ static int rndis_bind(struct usbnet *dev, struct usb_interface *intf)
         u32                     tmp;
 
         /* we can't rely on i/o from stack working, or stack allocation */
-        u.buf = kmalloc(1024, GFP_KERNEL);
+        u.buf = kmalloc(CONTROL_BUFFER_SIZE, GFP_KERNEL);
         if (!u.buf)
                 return -ENOMEM;
         retval = usbnet_generic_cdc_bind(dev, intf);
         if (retval < 0)
                 goto fail;
 
-        net->hard_header_len += sizeof (struct rndis_data_hdr);
-
-        /* initialize; max transfer is 16KB at full speed */
         u.init->msg_type = RNDIS_MSG_INIT;
         u.init->msg_len = ccpu2(sizeof *u.init);
         u.init->major_version = ccpu2(1);
         u.init->minor_version = ccpu2(0);
-        u.init->max_transfer_size = ccpu2(net->mtu + net->hard_header_len);
 
+        /* max transfer (in spec) is 0x4000 at full speed, but for
+         * TX we'll stick to one Ethernet packet plus RNDIS framing.
+         * For RX we handle drivers that zero-pad to end-of-packet.
+         * Don't let userspace change these settings.
+         */
+        net->hard_header_len += sizeof (struct rndis_data_hdr);
+        dev->hard_mtu = net->mtu + net->hard_header_len;
+
+        dev->rx_urb_size = dev->hard_mtu + (dev->maxpacket + 1);
+        dev->rx_urb_size &= ~(dev->maxpacket - 1);
+        u.init->max_transfer_size = cpu_to_le32(dev->rx_urb_size);
+
+        net->change_mtu = NULL;
         retval = rndis_command(dev, u.header);
         if (unlikely(retval < 0)) {
                 /* it might not even be an RNDIS device!! */
                 dev_err(&intf->dev, "RNDIS init failed, %d\n", retval);
+                goto fail_and_release;
+        }
+        tmp = le32_to_cpu(u.init_c->max_transfer_size);
+        if (tmp < dev->hard_mtu) {
+                dev_err(&intf->dev,
+                        "dev can't take %u byte packets (max %u)\n",
+                        dev->hard_mtu, tmp);
                 goto fail_and_release;
         }
-        dev->hard_mtu = le32_to_cpu(u.init_c->max_transfer_size);
+
         /* REVISIT:  peripheral "alignment" request is ignored ... */
-        dev_dbg(&intf->dev, "hard mtu %u, align %d\n", dev->hard_mtu,
+        dev_dbg(&intf->dev,
+                "hard mtu %u (%u from dev), rx buflen %Zu, align %d\n",
+                dev->hard_mtu, tmp, dev->rx_urb_size,
                 1 << le32_to_cpu(u.init_c->packet_alignment));
 
-        /* get designated host ethernet address */
-        memset(u.get, 0, sizeof *u.get);
+        /* Get designated host ethernet address.
+         *
+         * Adding a payload exactly the same size as the expected response
+         * payload is an evident requirement MSFT added for ActiveSync.
+         * This undocumented (and nonsensical) issue was found by sniffing
+         * protocol requests from the ActiveSync 4.1 Windows driver.
+         */
+        memset(u.get, 0, sizeof *u.get + 48);
         u.get->msg_type = RNDIS_MSG_QUERY;
-        u.get->msg_len = ccpu2(sizeof *u.get);
+        u.get->msg_len = ccpu2(sizeof *u.get + 48);
         u.get->oid = OID_802_3_PERMANENT_ADDRESS;
+        u.get->len = ccpu2(48);
+        u.get->offset = ccpu2(20);
 
         retval = rndis_command(dev, u.header);
         if (unlikely(retval < 0)) {
@@ -432,7 +471,7 @@ static int rndis_bind(struct usbnet *dev, struct usb_interface *intf)
                 goto fail_and_release;
         }
         tmp = le32_to_cpu(u.get_c->offset);
-        if (unlikely((tmp + 8) > (1024 - ETH_ALEN)
+        if (unlikely((tmp + 8) > (CONTROL_BUFFER_SIZE - ETH_ALEN)
                         || u.get_c->len != ccpu2(ETH_ALEN))) {
                 dev_err(&intf->dev, "rndis ethaddr off %d len %d ?\n",
                         tmp, le32_to_cpu(u.get_c->len));
@@ -598,6 +637,10 @@ static const struct usb_device_id	products [] = {
         /* RNDIS is MSFT's un-official variant of CDC ACM */
         USB_INTERFACE_INFO(USB_CLASS_COMM, 2 /* ACM */, 0x0ff),
         .driver_info = (unsigned long) &rndis_info,
+}, {
+        /* "ActiveSync" is an undocumented variant of RNDIS, used in WM5 */
+        USB_INTERFACE_INFO(USB_CLASS_MISC, 1, 1),
+        .driver_info = (unsigned long) &rndis_info,
 },
         { },            // END
 };