2 * Ethernet interface part of the LG VL600 LTE modem (4G dongle)
4 * Copyright (C) 2011 Intel Corporation
5 * Author: Andrzej Zaborowski <balrogg@gmail.com>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, see <http://www.gnu.org/licenses/>.
20 #include <linux/etherdevice.h>
21 #include <linux/ethtool.h>
22 #include <linux/mii.h>
23 #include <linux/usb.h>
24 #include <linux/usb/cdc.h>
25 #include <linux/usb/usbnet.h>
26 #include <linux/if_ether.h>
27 #include <linux/if_arp.h>
28 #include <linux/inetdevice.h>
29 #include <linux/module.h>
32 * The device has a CDC ACM port for modem control (it claims to be
33 * CDC ACM anyway) and a CDC Ethernet port for actual network data.
34 * It will however ignore data on both ports that is not encapsulated
35 * in a specific way, any data returned is also encapsulated the same
36 * way. The headers don't seem to follow any popular standard.
38 * This driver adds and strips these headers from the ethernet frames
39 * sent/received from the CDC Ethernet port. The proprietary header
40 * replaces the standard ethernet header in a packet so only actual
41 * ethernet frames are allowed. The headers allow some form of
42 * multiplexing by using non standard values of the .h_proto field.
43 * Windows/Mac drivers do send a couple of such frames to the device
44 * during initialisation, with protocol set to 0x0906 or 0x0b06 and (what
45 * seems to be) a flag in the .dummy_flags. This doesn't seem necessary
46 * for modem operation but can possibly be used for GPS or other funcitons.
49 struct vl600_frame_hdr
{
56 } __attribute__((packed
));
58 struct vl600_pkt_hdr
{
62 } __attribute__((packed
));
65 struct sk_buff
*current_rx_buf
;
68 static int vl600_bind(struct usbnet
*dev
, struct usb_interface
*intf
)
71 struct vl600_state
*s
= kzalloc(sizeof(struct vl600_state
), GFP_KERNEL
);
76 ret
= usbnet_cdc_bind(dev
, intf
);
84 /* ARP packets don't go through, but they're also of no use. The
85 * subnet has only two hosts anyway: us and the gateway / DHCP
86 * server (probably simulated by modem firmware or network operator)
87 * whose address changes everytime we connect to the intarwebz and
88 * who doesn't bother answering ARP requests either. So hardware
89 * addresses have no meaning, the destination and the source of every
90 * packet depend only on whether it is on the IN or OUT endpoint. */
91 dev
->net
->flags
|= IFF_NOARP
;
92 /* IPv6 NDP relies on multicast. Enable it by default. */
93 dev
->net
->flags
|= IFF_MULTICAST
;
98 static void vl600_unbind(struct usbnet
*dev
, struct usb_interface
*intf
)
100 struct vl600_state
*s
= dev
->driver_priv
;
102 if (s
->current_rx_buf
)
103 dev_kfree_skb(s
->current_rx_buf
);
107 return usbnet_cdc_unbind(dev
, intf
);
110 static int vl600_rx_fixup(struct usbnet
*dev
, struct sk_buff
*skb
)
112 struct vl600_frame_hdr
*frame
;
113 struct vl600_pkt_hdr
*packet
;
114 struct ethhdr
*ethhdr
;
115 int packet_len
, count
;
116 struct sk_buff
*buf
= skb
;
117 struct sk_buff
*clone
;
118 struct vl600_state
*s
= dev
->driver_priv
;
120 /* Frame lengths are generally 4B multiplies but every couple of
121 * hours there's an odd number of bytes sized yet correct frame,
122 * so don't require this. */
124 /* Allow a packet (or multiple packets batched together) to be
125 * split across many frames. We don't allow a new batch to
126 * begin in the same frame another one is ending however, and no
127 * leading or trailing pad bytes. */
128 if (s
->current_rx_buf
) {
129 frame
= (struct vl600_frame_hdr
*) s
->current_rx_buf
->data
;
130 if (skb
->len
+ s
->current_rx_buf
->len
>
131 le32_to_cpup(&frame
->len
)) {
132 netif_err(dev
, ifup
, dev
->net
, "Fragment too long\n");
133 dev
->net
->stats
.rx_length_errors
++;
137 buf
= s
->current_rx_buf
;
138 skb_put_data(buf
, skb
->data
, skb
->len
);
139 } else if (skb
->len
< 4) {
140 netif_err(dev
, ifup
, dev
->net
, "Frame too short\n");
141 dev
->net
->stats
.rx_length_errors
++;
145 frame
= (struct vl600_frame_hdr
*) buf
->data
;
146 /* Yes, check that frame->magic == 0x53544448 (or 0x44544d48),
147 * otherwise we may run out of memory w/a bad packet */
148 if (ntohl(frame
->magic
) != 0x53544448 &&
149 ntohl(frame
->magic
) != 0x44544d48)
152 if (buf
->len
< sizeof(*frame
) ||
153 buf
->len
!= le32_to_cpup(&frame
->len
)) {
154 /* Save this fragment for later assembly */
155 if (s
->current_rx_buf
)
158 s
->current_rx_buf
= skb_copy_expand(skb
, 0,
159 le32_to_cpup(&frame
->len
), GFP_ATOMIC
);
160 if (!s
->current_rx_buf
) {
161 netif_err(dev
, ifup
, dev
->net
, "Reserving %i bytes "
162 "for packet assembly failed.\n",
163 le32_to_cpup(&frame
->len
));
164 dev
->net
->stats
.rx_errors
++;
170 count
= le32_to_cpup(&frame
->pkt_cnt
);
172 skb_pull(buf
, sizeof(*frame
));
175 if (buf
->len
< sizeof(*packet
)) {
176 netif_err(dev
, ifup
, dev
->net
, "Packet too short\n");
180 packet
= (struct vl600_pkt_hdr
*) buf
->data
;
181 packet_len
= sizeof(*packet
) + le32_to_cpup(&packet
->len
);
182 if (packet_len
> buf
->len
) {
183 netif_err(dev
, ifup
, dev
->net
,
184 "Bad packet length stored in header\n");
188 /* Packet header is same size as the ethernet header
189 * (sizeof(*packet) == sizeof(*ethhdr)), additionally
190 * the h_proto field is in the same place so we just leave it
191 * alone and fill in the remaining fields.
193 ethhdr
= (struct ethhdr
*) skb
->data
;
194 if (be16_to_cpup(ðhdr
->h_proto
) == ETH_P_ARP
&&
196 /* Copy the addresses from packet contents */
197 memcpy(ethhdr
->h_source
,
198 &buf
->data
[sizeof(*ethhdr
) + 0x8],
200 memcpy(ethhdr
->h_dest
,
201 &buf
->data
[sizeof(*ethhdr
) + 0x12],
204 eth_zero_addr(ethhdr
->h_source
);
205 memcpy(ethhdr
->h_dest
, dev
->net
->dev_addr
, ETH_ALEN
);
207 /* Inbound IPv6 packets have an IPv4 ethertype (0x800)
208 * for some reason. Peek at the L3 header to check
209 * for IPv6 packets, and set the ethertype to IPv6
210 * (0x86dd) so Linux can understand it.
212 if ((buf
->data
[sizeof(*ethhdr
)] & 0xf0) == 0x60)
213 ethhdr
->h_proto
= htons(ETH_P_IPV6
);
217 /* Not the last packet in this batch */
218 clone
= skb_clone(buf
, GFP_ATOMIC
);
222 skb_trim(clone
, packet_len
);
223 usbnet_skb_return(dev
, clone
);
225 skb_pull(buf
, (packet_len
+ 3) & ~3);
227 skb_trim(buf
, packet_len
);
229 if (s
->current_rx_buf
) {
230 usbnet_skb_return(dev
, buf
);
231 s
->current_rx_buf
= NULL
;
240 if (s
->current_rx_buf
) {
241 dev_kfree_skb_any(s
->current_rx_buf
);
242 s
->current_rx_buf
= NULL
;
244 dev
->net
->stats
.rx_errors
++;
248 static struct sk_buff
*vl600_tx_fixup(struct usbnet
*dev
,
249 struct sk_buff
*skb
, gfp_t flags
)
252 struct vl600_frame_hdr
*frame
;
253 struct vl600_pkt_hdr
*packet
;
254 static uint32_t serial
= 1;
255 int orig_len
= skb
->len
- sizeof(struct ethhdr
);
256 int full_len
= (skb
->len
+ sizeof(struct vl600_frame_hdr
) + 3) & ~3;
258 frame
= (struct vl600_frame_hdr
*) skb
->data
;
259 if (skb
->len
> sizeof(*frame
) && skb
->len
== le32_to_cpup(&frame
->len
))
260 return skb
; /* Already encapsulated? */
262 if (skb
->len
< sizeof(struct ethhdr
))
263 /* Drop, device can only deal with ethernet packets */
266 if (!skb_cloned(skb
)) {
267 int headroom
= skb_headroom(skb
);
268 int tailroom
= skb_tailroom(skb
);
270 if (tailroom
>= full_len
- skb
->len
- sizeof(*frame
) &&
271 headroom
>= sizeof(*frame
))
272 /* There's enough head and tail room */
275 if (headroom
+ tailroom
+ skb
->len
>= full_len
) {
276 /* There's enough total room, just readjust */
277 skb
->data
= memmove(skb
->head
+ sizeof(*frame
),
278 skb
->data
, skb
->len
);
279 skb_set_tail_pointer(skb
, skb
->len
);
284 /* Alloc a new skb with the required size */
285 ret
= skb_copy_expand(skb
, sizeof(struct vl600_frame_hdr
), full_len
-
286 skb
->len
- sizeof(struct vl600_frame_hdr
), flags
);
287 dev_kfree_skb_any(skb
);
293 /* Packet header is same size as ethernet packet header
294 * (sizeof(*packet) == sizeof(struct ethhdr)), additionally the
295 * h_proto field is in the same place so we just leave it alone and
296 * overwrite the remaining fields.
298 packet
= (struct vl600_pkt_hdr
*) skb
->data
;
299 /* The VL600 wants IPv6 packets to have an IPv4 ethertype
300 * Since this modem only supports IPv4 and IPv6, just set all
301 * frames to 0x0800 (ETH_P_IP)
303 packet
->h_proto
= htons(ETH_P_IP
);
304 memset(&packet
->dummy
, 0, sizeof(packet
->dummy
));
305 packet
->len
= cpu_to_le32(orig_len
);
307 frame
= skb_push(skb
, sizeof(*frame
));
308 memset(frame
, 0, sizeof(*frame
));
309 frame
->len
= cpu_to_le32(full_len
);
310 frame
->serial
= cpu_to_le32(serial
++);
311 frame
->pkt_cnt
= cpu_to_le32(1);
313 if (skb
->len
< full_len
) /* Pad */
314 skb_put(skb
, full_len
- skb
->len
);
319 static const struct driver_info vl600_info
= {
320 .description
= "LG VL600 modem",
321 .flags
= FLAG_RX_ASSEMBLE
| FLAG_WWAN
,
323 .unbind
= vl600_unbind
,
324 .status
= usbnet_cdc_status
,
325 .rx_fixup
= vl600_rx_fixup
,
326 .tx_fixup
= vl600_tx_fixup
,
329 static const struct usb_device_id products
[] = {
331 USB_DEVICE_AND_INTERFACE_INFO(0x1004, 0x61aa, USB_CLASS_COMM
,
332 USB_CDC_SUBCLASS_ETHERNET
, USB_CDC_PROTO_NONE
),
333 .driver_info
= (unsigned long) &vl600_info
,
337 MODULE_DEVICE_TABLE(usb
, products
);
339 static struct usb_driver lg_vl600_driver
= {
341 .id_table
= products
,
342 .probe
= usbnet_probe
,
343 .disconnect
= usbnet_disconnect
,
344 .suspend
= usbnet_suspend
,
345 .resume
= usbnet_resume
,
346 .disable_hub_initiated_lpm
= 1,
349 module_usb_driver(lg_vl600_driver
);
351 MODULE_AUTHOR("Anrzej Zaborowski");
352 MODULE_DESCRIPTION("LG-VL600 modem's ethernet link");
353 MODULE_LICENSE("GPL");