2019-04-16 14:08:46

by Romain Izard

[permalink] [raw]
Subject: [PATCH 1/2] usb: gadget: f_ncm: Fix NTP-32 support

When connecting a CDC-NCM gadget to an host that uses the NTP-32 mode,
or that relies on the default CRC setting, the current implementation gets
confused, and does not expect the correct signature for its packets.

Fix this, by ensuring that the ndp_sign member in the f_ncm structure
always contain a valid value.

Signed-off-by: Romain Izard <[email protected]>
---
drivers/usb/gadget/function/f_ncm.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/gadget/function/f_ncm.c b/drivers/usb/gadget/function/f_ncm.c
index 5780fba620ab..d5c47e7a7f61 100644
--- a/drivers/usb/gadget/function/f_ncm.c
+++ b/drivers/usb/gadget/function/f_ncm.c
@@ -35,9 +35,7 @@

/* to trigger crc/non-crc ndp signature */

-#define NCM_NDP_HDR_CRC_MASK 0x01000000
#define NCM_NDP_HDR_CRC 0x01000000
-#define NCM_NDP_HDR_NOCRC 0x00000000

enum ncm_notify_state {
NCM_NOTIFY_NONE, /* don't notify */
@@ -526,6 +524,7 @@ static inline void ncm_reset_values(struct f_ncm *ncm)
{
ncm->parser_opts = &ndp16_opts;
ncm->is_crc = false;
+ ncm->ndp_sign = ncm->parser_opts->ndp_sign;
ncm->port.cdc_filter = DEFAULT_FILTER;

/* doesn't make sense for ncm, fixed size used */
@@ -805,25 +804,20 @@ static int ncm_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
| USB_CDC_SET_CRC_MODE:
{
- int ndp_hdr_crc = 0;
-
if (w_length != 0 || w_index != ncm->ctrl_id)
goto invalid;
switch (w_value) {
case 0x0000:
ncm->is_crc = false;
- ndp_hdr_crc = NCM_NDP_HDR_NOCRC;
DBG(cdev, "non-CRC mode selected\n");
break;
case 0x0001:
ncm->is_crc = true;
- ndp_hdr_crc = NCM_NDP_HDR_CRC;
DBG(cdev, "CRC mode selected\n");
break;
default:
goto invalid;
}
- ncm->ndp_sign = ncm->parser_opts->ndp_sign | ndp_hdr_crc;
value = 0;
break;
}
@@ -840,6 +834,8 @@ static int ncm_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
ctrl->bRequestType, ctrl->bRequest,
w_value, w_index, w_length);
}
+ ncm->ndp_sign = ncm->parser_opts->ndp_sign |
+ (ncm->is_crc ? NCM_NDP_HDR_CRC : 0);

/* respond with data transfer or status phase? */
if (value >= 0) {
--
2.17.1


2019-04-16 14:10:43

by Romain Izard

[permalink] [raw]
Subject: [PATCH 2/2] usb: gadget: f_ncm: Add OS descriptor support

To be able to use the default USB class drivers available in Microsoft
Windows, we need to add OS descriptors to the exported USB gadget to
tell the OS that we are compatible with the built-in drivers.

Copy the OS descriptor support from f_rndis into f_ncm. As a result,
using the WINNCM compatible ID, the UsbNcm driver is loaded on
enumeration without the need for a custom driver or inf file.

Signed-off-by: Romain Izard <[email protected]>
---
drivers/usb/gadget/function/f_ncm.c | 47 +++++++++++++++++++++++++++--
drivers/usb/gadget/function/u_ncm.h | 3 ++
2 files changed, 47 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/gadget/function/f_ncm.c b/drivers/usb/gadget/function/f_ncm.c
index d5c47e7a7f61..2d6e76e4cffa 100644
--- a/drivers/usb/gadget/function/f_ncm.c
+++ b/drivers/usb/gadget/function/f_ncm.c
@@ -23,6 +23,7 @@
#include "u_ether.h"
#include "u_ether_configfs.h"
#include "u_ncm.h"
+#include "configfs.h"

/*
* This function is a "CDC Network Control Model" (CDC NCM) Ethernet link.
@@ -1391,6 +1392,16 @@ static int ncm_bind(struct usb_configuration *c, struct usb_function *f)
return -EINVAL;

ncm_opts = container_of(f->fi, struct f_ncm_opts, func_inst);
+
+ if (cdev->use_os_string) {
+ f->os_desc_table = kzalloc(sizeof(*f->os_desc_table),
+ GFP_KERNEL);
+ if (!f->os_desc_table)
+ return -ENOMEM;
+ f->os_desc_n = 1;
+ f->os_desc_table[0].os_desc = &ncm_opts->ncm_os_desc;
+ }
+
/*
* in drivers/usb/gadget/configfs.c:configfs_composite_bind()
* configurations are bound in sequence with list_for_each_entry,
@@ -1404,13 +1415,15 @@ static int ncm_bind(struct usb_configuration *c, struct usb_function *f)
status = gether_register_netdev(ncm_opts->net);
mutex_unlock(&ncm_opts->lock);
if (status)
- return status;
+ goto fail;
ncm_opts->bound = true;
}
us = usb_gstrings_attach(cdev, ncm_strings,
ARRAY_SIZE(ncm_string_defs));
- if (IS_ERR(us))
- return PTR_ERR(us);
+ if (IS_ERR(us)) {
+ status = PTR_ERR(us);
+ goto fail;
+ }
ncm_control_intf.iInterface = us[STRING_CTRL_IDX].id;
ncm_data_nop_intf.iInterface = us[STRING_DATA_IDX].id;
ncm_data_intf.iInterface = us[STRING_DATA_IDX].id;
@@ -1427,6 +1440,10 @@ static int ncm_bind(struct usb_configuration *c, struct usb_function *f)
ncm_control_intf.bInterfaceNumber = status;
ncm_union_desc.bMasterInterface0 = status;

+ if (cdev->use_os_string)
+ f->os_desc_table[0].if_id =
+ ncm_iad_desc.bFirstInterface;
+
status = usb_interface_id(c, f);
if (status < 0)
goto fail;
@@ -1506,6 +1523,9 @@ static int ncm_bind(struct usb_configuration *c, struct usb_function *f)
return 0;

fail:
+ kfree(f->os_desc_table);
+ f->os_desc_n = 0;
+
if (ncm->notify_req) {
kfree(ncm->notify_req->buf);
usb_ep_free_request(ncm->notify, ncm->notify_req);
@@ -1560,16 +1580,22 @@ static void ncm_free_inst(struct usb_function_instance *f)
gether_cleanup(netdev_priv(opts->net));
else
free_netdev(opts->net);
+ kfree(opts->ncm_interf_group);
kfree(opts);
}

static struct usb_function_instance *ncm_alloc_inst(void)
{
struct f_ncm_opts *opts;
+ struct usb_os_desc *descs[1];
+ char *names[1];
+ struct config_group *ncm_interf_group;

opts = kzalloc(sizeof(*opts), GFP_KERNEL);
if (!opts)
return ERR_PTR(-ENOMEM);
+ opts->ncm_os_desc.ext_compat_id = opts->ncm_ext_compat_id;
+
mutex_init(&opts->lock);
opts->func_inst.free_func_inst = ncm_free_inst;
opts->net = gether_setup_default();
@@ -1578,8 +1604,20 @@ static struct usb_function_instance *ncm_alloc_inst(void)
kfree(opts);
return ERR_CAST(net);
}
+ INIT_LIST_HEAD(&opts->ncm_os_desc.ext_prop);
+
+ descs[0] = &opts->ncm_os_desc;
+ names[0] = "ncm";

config_group_init_type_name(&opts->func_inst.group, "", &ncm_func_type);
+ ncm_interf_group =
+ usb_os_desc_prepare_interf_dir(&opts->func_inst.group, 1, descs,
+ names, THIS_MODULE);
+ if (IS_ERR(ncm_interf_group)) {
+ ncm_free_inst(&opts->func_inst);
+ return ERR_CAST(ncm_interf_group);
+ }
+ opts->ncm_interf_group = ncm_interf_group;

return &opts->func_inst;
}
@@ -1605,6 +1643,9 @@ static void ncm_unbind(struct usb_configuration *c, struct usb_function *f)

hrtimer_cancel(&ncm->task_timer);

+ kfree(f->os_desc_table);
+ f->os_desc_n = 0;
+
ncm_string_defs[0].id = 0;
usb_free_all_descriptors(f);

diff --git a/drivers/usb/gadget/function/u_ncm.h b/drivers/usb/gadget/function/u_ncm.h
index d483e45c0f77..70da3201a1d0 100644
--- a/drivers/usb/gadget/function/u_ncm.h
+++ b/drivers/usb/gadget/function/u_ncm.h
@@ -20,6 +20,9 @@ struct f_ncm_opts {
struct net_device *net;
bool bound;

+ struct config_group *ncm_interf_group;
+ struct usb_os_desc ncm_os_desc;
+ char ncm_ext_compat_id[16];
/*
* Read/write access to configfs attributes is handled by configfs.
*
--
2.17.1