1 From a2d274c62e44b1995c170595db3865c6fe701226 Mon Sep 17 00:00:00 2001
2 From: Foster Snowhill <forst@pen.gy>
3 Date: Wed, 7 Jun 2023 15:57:01 +0200
4 Subject: [PATCH 3/4] usbnet: ipheth: add CDC NCM support
6 Recent iOS releases support CDC NCM encapsulation on RX. This mode is
7 the default on macOS and Windows. In this mode, an iOS device may include
8 one or more Ethernet frames inside a single URB.
10 Freshly booted iOS devices start in legacy mode, but are put into
11 NCM mode by the official Apple driver. When reconnecting such a device
12 from a macOS/Windows machine to a Linux host, the device stays in
13 NCM mode, making it unusable with the legacy ipheth driver code.
15 To correctly support such a device, the driver has to either support
16 the NCM mode too, or put the device back into legacy mode.
18 To match the behaviour of the macOS/Windows driver, and since there
19 is no documented control command to revert to legacy mode, implement
20 NCM support. The device is attempted to be put into NCM mode by default,
21 and falls back to legacy mode if the attempt fails.
23 Signed-off-by: Foster Snowhill <forst@pen.gy>
24 Tested-by: Georgi Valkov <gvalkov@gmail.com>
25 Signed-off-by: David S. Miller <davem@davemloft.net>
27 drivers/net/usb/ipheth.c | 180 +++++++++++++++++++++++++++++++++------
28 1 file changed, 155 insertions(+), 25 deletions(-)
30 --- a/drivers/net/usb/ipheth.c
31 +++ b/drivers/net/usb/ipheth.c
33 #include <linux/ethtool.h>
34 #include <linux/usb.h>
35 #include <linux/workqueue.h>
36 +#include <linux/usb/cdc.h>
38 #define USB_VENDOR_APPLE 0x05ac
41 #define IPHETH_USBINTF_SUBCLASS 253
42 #define IPHETH_USBINTF_PROTO 1
44 -#define IPHETH_BUF_SIZE 1514
45 #define IPHETH_IP_ALIGN 2 /* padding at front of URB */
46 +#define IPHETH_NCM_HEADER_SIZE (12 + 96) /* NCMH + NCM0 */
47 +#define IPHETH_TX_BUF_SIZE ETH_FRAME_LEN
48 +#define IPHETH_RX_BUF_SIZE_LEGACY (IPHETH_IP_ALIGN + ETH_FRAME_LEN)
49 +#define IPHETH_RX_BUF_SIZE_NCM 65536
51 #define IPHETH_TX_TIMEOUT (5 * HZ)
53 #define IPHETH_INTFNUM 2
55 #define IPHETH_CTRL_TIMEOUT (5 * HZ)
57 #define IPHETH_CMD_GET_MACADDR 0x00
58 +#define IPHETH_CMD_ENABLE_NCM 0x04
59 #define IPHETH_CMD_CARRIER_CHECK 0x45
61 #define IPHETH_CARRIER_CHECK_TIMEOUT round_jiffies_relative(1 * HZ)
62 @@ -97,6 +103,8 @@ struct ipheth_device {
64 struct delayed_work carrier_work;
65 bool confirmed_pairing;
66 + int (*rcvbulk_callback)(struct urb *urb);
70 static int ipheth_rx_submit(struct ipheth_device *dev, gfp_t mem_flags);
71 @@ -116,12 +124,12 @@ static int ipheth_alloc_urbs(struct iphe
75 - tx_buf = usb_alloc_coherent(iphone->udev, IPHETH_BUF_SIZE,
76 + tx_buf = usb_alloc_coherent(iphone->udev, IPHETH_TX_BUF_SIZE,
77 GFP_KERNEL, &tx_urb->transfer_dma);
81 - rx_buf = usb_alloc_coherent(iphone->udev, IPHETH_BUF_SIZE + IPHETH_IP_ALIGN,
82 + rx_buf = usb_alloc_coherent(iphone->udev, iphone->rx_buf_len,
83 GFP_KERNEL, &rx_urb->transfer_dma);
86 @@ -134,7 +142,7 @@ static int ipheth_alloc_urbs(struct iphe
90 - usb_free_coherent(iphone->udev, IPHETH_BUF_SIZE, tx_buf,
91 + usb_free_coherent(iphone->udev, IPHETH_TX_BUF_SIZE, tx_buf,
92 tx_urb->transfer_dma);
95 @@ -146,9 +154,9 @@ error_nomem:
97 static void ipheth_free_urbs(struct ipheth_device *iphone)
99 - usb_free_coherent(iphone->udev, IPHETH_BUF_SIZE + IPHETH_IP_ALIGN, iphone->rx_buf,
100 + usb_free_coherent(iphone->udev, iphone->rx_buf_len, iphone->rx_buf,
101 iphone->rx_urb->transfer_dma);
102 - usb_free_coherent(iphone->udev, IPHETH_BUF_SIZE, iphone->tx_buf,
103 + usb_free_coherent(iphone->udev, IPHETH_TX_BUF_SIZE, iphone->tx_buf,
104 iphone->tx_urb->transfer_dma);
105 usb_free_urb(iphone->rx_urb);
106 usb_free_urb(iphone->tx_urb);
107 @@ -160,15 +168,106 @@ static void ipheth_kill_urbs(struct iphe
108 usb_kill_urb(dev->rx_urb);
111 -static void ipheth_rcvbulk_callback(struct urb *urb)
112 +static int ipheth_consume_skb(char *buf, int len, struct ipheth_device *dev)
114 - struct ipheth_device *dev;
118 + skb = dev_alloc_skb(len);
120 + dev->net->stats.rx_dropped++;
124 + skb_put_data(skb, buf, len);
125 + skb->dev = dev->net;
126 + skb->protocol = eth_type_trans(skb, dev->net);
128 + dev->net->stats.rx_packets++;
129 + dev->net->stats.rx_bytes += len;
135 +static int ipheth_rcvbulk_callback_legacy(struct urb *urb)
137 + struct ipheth_device *dev;
141 + dev = urb->context;
143 + if (urb->actual_length <= IPHETH_IP_ALIGN) {
144 + dev->net->stats.rx_length_errors++;
147 + len = urb->actual_length - IPHETH_IP_ALIGN;
148 + buf = urb->transfer_buffer + IPHETH_IP_ALIGN;
150 + return ipheth_consume_skb(buf, len, dev);
153 +static int ipheth_rcvbulk_callback_ncm(struct urb *urb)
155 + struct usb_cdc_ncm_nth16 *ncmh;
156 + struct usb_cdc_ncm_ndp16 *ncm0;
157 + struct usb_cdc_ncm_dpe16 *dpe;
158 + struct ipheth_device *dev;
159 + int retval = -EINVAL;
165 + if (urb->actual_length < IPHETH_NCM_HEADER_SIZE) {
166 + dev->net->stats.rx_length_errors++;
170 + ncmh = urb->transfer_buffer;
171 + if (ncmh->dwSignature != cpu_to_le32(USB_CDC_NCM_NTH16_SIGN) ||
172 + le16_to_cpu(ncmh->wNdpIndex) >= urb->actual_length) {
173 + dev->net->stats.rx_errors++;
177 + ncm0 = urb->transfer_buffer + le16_to_cpu(ncmh->wNdpIndex);
178 + if (ncm0->dwSignature != cpu_to_le32(USB_CDC_NCM_NDP16_NOCRC_SIGN) ||
179 + le16_to_cpu(ncmh->wHeaderLength) + le16_to_cpu(ncm0->wLength) >=
180 + urb->actual_length) {
181 + dev->net->stats.rx_errors++;
186 + while (le16_to_cpu(dpe->wDatagramIndex) != 0 &&
187 + le16_to_cpu(dpe->wDatagramLength) != 0) {
188 + if (le16_to_cpu(dpe->wDatagramIndex) >= urb->actual_length ||
189 + le16_to_cpu(dpe->wDatagramIndex) +
190 + le16_to_cpu(dpe->wDatagramLength) > urb->actual_length) {
191 + dev->net->stats.rx_length_errors++;
195 + buf = urb->transfer_buffer + le16_to_cpu(dpe->wDatagramIndex);
196 + len = le16_to_cpu(dpe->wDatagramLength);
198 + retval = ipheth_consume_skb(buf, len, dev);
208 +static void ipheth_rcvbulk_callback(struct urb *urb)
210 + struct ipheth_device *dev;
211 + int retval, status;
213 + dev = urb->context;
217 @@ -191,25 +290,27 @@ static void ipheth_rcvbulk_callback(stru
218 dev->net->stats.rx_length_errors++;
221 - len = urb->actual_length - IPHETH_IP_ALIGN;
222 - buf = urb->transfer_buffer + IPHETH_IP_ALIGN;
224 - skb = dev_alloc_skb(len);
226 - dev_err(&dev->intf->dev, "%s: dev_alloc_skb: -ENOMEM\n",
228 - dev->net->stats.rx_dropped++;
229 + /* RX URBs starting with 0x00 0x01 do not encapsulate Ethernet frames,
230 + * but rather are control frames. Their purpose is not documented, and
231 + * they don't affect driver functionality, okay to drop them.
232 + * There is usually just one 4-byte control frame as the very first
233 + * URB received from the bulk IN endpoint.
236 + (((char *)urb->transfer_buffer)[0] == 0 &&
237 + ((char *)urb->transfer_buffer)[1] == 1))
240 + retval = dev->rcvbulk_callback(urb);
242 + dev_err(&dev->intf->dev, "%s: callback retval: %d\n",
247 - skb_put_data(skb, buf, len);
248 - skb->dev = dev->net;
249 - skb->protocol = eth_type_trans(skb, dev->net);
251 - dev->net->stats.rx_packets++;
252 - dev->net->stats.rx_bytes += len;
254 dev->confirmed_pairing = true;
256 ipheth_rx_submit(dev, GFP_ATOMIC);
259 @@ -310,6 +411,27 @@ static int ipheth_get_macaddr(struct iph
263 +static int ipheth_enable_ncm(struct ipheth_device *dev)
265 + struct usb_device *udev = dev->udev;
268 + retval = usb_control_msg(udev,
269 + usb_sndctrlpipe(udev, IPHETH_CTRL_ENDP),
270 + IPHETH_CMD_ENABLE_NCM, /* request */
271 + 0x41, /* request type */
276 + IPHETH_CTRL_TIMEOUT);
278 + dev_info(&dev->intf->dev, "%s: usb_control_msg: %d\n",
284 static int ipheth_rx_submit(struct ipheth_device *dev, gfp_t mem_flags)
286 struct usb_device *udev = dev->udev;
287 @@ -317,7 +439,7 @@ static int ipheth_rx_submit(struct iphet
289 usb_fill_bulk_urb(dev->rx_urb, udev,
290 usb_rcvbulkpipe(udev, dev->bulk_in),
291 - dev->rx_buf, IPHETH_BUF_SIZE + IPHETH_IP_ALIGN,
292 + dev->rx_buf, dev->rx_buf_len,
293 ipheth_rcvbulk_callback,
295 dev->rx_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
296 @@ -365,7 +487,7 @@ static netdev_tx_t ipheth_tx(struct sk_b
300 - if (skb->len > IPHETH_BUF_SIZE) {
301 + if (skb->len > IPHETH_TX_BUF_SIZE) {
302 WARN(1, "%s: skb too large: %d bytes\n", __func__, skb->len);
303 dev->net->stats.tx_dropped++;
304 dev_kfree_skb_any(skb);
305 @@ -448,6 +570,8 @@ static int ipheth_probe(struct usb_inter
308 dev->confirmed_pairing = false;
309 + dev->rx_buf_len = IPHETH_RX_BUF_SIZE_LEGACY;
310 + dev->rcvbulk_callback = ipheth_rcvbulk_callback_legacy;
311 /* Set up endpoints */
312 hintf = usb_altnum_to_altsetting(intf, IPHETH_ALT_INTFNUM);
314 @@ -479,6 +603,12 @@ static int ipheth_probe(struct usb_inter
316 goto err_get_macaddr;
318 + retval = ipheth_enable_ncm(dev);
320 + dev->rx_buf_len = IPHETH_RX_BUF_SIZE_NCM;
321 + dev->rcvbulk_callback = ipheth_rcvbulk_callback_ncm;
324 INIT_DELAYED_WORK(&dev->carrier_work, ipheth_carrier_check_work);
326 retval = ipheth_alloc_urbs(dev);