rndis_host learns ActiveSync basics

Windows Mobile 5 based devices described as supporting "ActiveSync":

 - Speak RNDIS but lack the CDC and union descriptors.  This patch
   updates the cdc ethernet code to fake ACM descriptors we need.

 - Require RNDIS_MSG_QUERY messages to include a buffer of the size the
   response should generate.  This patch updates the rndis host code to
   pass this will-be-ignored data.

The resulting RNDIS host code has been reported to work with several
WM5 based devices.

(Note that a fancier patch is available at synce.sf.net.)


Some bugfixes, affecting not just ActiveSync:
    (a)	when cleaning up after RNDS init fails, scrub the second interface
	just like cdc_ether does, so disconnect won't oops.
    (b)	handle peripherals that use the pad-to-end-of-packet option; some
	devices can't talk to us if that option doesn't work.
    (c)	when choosing configurations, don't forget about an RNDIS config
	just because the RNDIS driver is dynamically linked.

Cleanup, streamlining, bugfixes, Kconfig, and matching hub driver update.
Also for paranoia's sake, refuse to talk to something that looks like a
real modem instead of RNDIS.

Signed-off-by: Ole Andre Vadla Ravnaas <oleavr@gmail.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 58 insertions, 2 deletions

diff --git a/drivers/usb/net/cdc_ether.c b/drivers/usb/net/cdc_ether.c
index 44a91547146e..e5cdafa258dd 100644
--- a/drivers/usb/net/cdc_ether.c
+++ b/drivers/usb/net/cdc_ether.c
@@ -1,6 +1,7 @@
 /*
  * CDC Ethernet based networking peripherals
  * Copyright (C) 2003-2005 by David Brownell
+ * Copyright (C) 2006 by Ole Andre Vadla Ravnas (ActiveSync)
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -35,6 +36,29 @@
 #include "usbnet.h"
 
 
+#if defined(CONFIG_USB_NET_RNDIS_HOST) || defined(CONFIG_USB_NET_RNDIS_HOST_MODULE)
+
+static int is_rndis(struct usb_interface_descriptor *desc)
+{
+        return desc->bInterfaceClass == USB_CLASS_COMM
+                && desc->bInterfaceSubClass == 2
+                && desc->bInterfaceProtocol == 0xff;
+}
+
+static int is_activesync(struct usb_interface_descriptor *desc)
+{
+        return desc->bInterfaceClass == USB_CLASS_MISC
+                && desc->bInterfaceSubClass == 1
+                && desc->bInterfaceProtocol == 1;
+}
+
+#else
+
+#define is_rndis(desc)          0
+#define is_activesync(desc)     0
+
+#endif
+
 /*
  * probes control interface, claims data interface, collects the bulk
  * endpoints, activates data interface (if needed), maybe sets MTU.
@@ -71,7 +95,8 @@ int usbnet_generic_cdc_bind(struct usbnet *dev, struct usb_interface *intf)
         /* this assumes that if there's a non-RNDIS vendor variant
          * of cdc-acm, it'll fail RNDIS requests cleanly.
          */
-        rndis = (intf->cur_altsetting->desc.bInterfaceProtocol == 0xff);
+        rndis = is_rndis(&intf->cur_altsetting->desc)
+                || is_activesync(&intf->cur_altsetting->desc);
 
         memset(info, 0, sizeof *info);
         info->control = intf;
@@ -99,6 +124,23 @@ int usbnet_generic_cdc_bind(struct usbnet *dev, struct usb_interface *intf)
                                 goto bad_desc;
                         }
                         break;
+                case USB_CDC_ACM_TYPE:
+                        /* paranoia:  disambiguate a "real" vendor-specific
+                         * modem interface from an RNDIS non-modem.
+                         */
+                        if (rndis) {
+                                struct usb_cdc_acm_descriptor *d;
+
+                                d = (void *) buf;
+                                if (d->bmCapabilities) {
+                                        dev_dbg(&intf->dev,
+                                                "ACM capabilities %02x, "
+                                                "not really RNDIS?\n",
+                                                d->bmCapabilities);
+                                        goto bad_desc;
+                                }
+                        }
+                        break;
                 case USB_CDC_UNION_TYPE:
                         if (info->u) {
                                 dev_dbg(&intf->dev, "extra CDC union\n");
@@ -171,7 +213,21 @@ next_desc:
                 buf += buf [0];
         }
 
-        if (!info->header || !info->u || (!rndis && !info->ether)) {
+        /* Microsoft ActiveSync based RNDIS devices lack the CDC descriptors,
+         * so we'll hard-wire the interfaces and not check for descriptors.
+         */
+        if (is_activesync(&intf->cur_altsetting->desc) && !info->u) {
+                info->control = usb_ifnum_to_if(dev->udev, 0);
+                info->data = usb_ifnum_to_if(dev->udev, 1);
+                if (!info->control || !info->data) {
+                        dev_dbg(&intf->dev,
+                                "activesync: master #0/%p slave #1/%p\n",
+                                info->control,
+                                info->data);
+                        goto bad_desc;
+                }
+
+        } else if (!info->header || !info->u || (!rndis && !info->ether)) {
                 dev_dbg(&intf->dev, "missing cdc %s%s%sdescriptor\n",
                         info->header ? "" : "header ",
                         info->u ? "" : "union ",