blob: 1d83ccfd72778ea2e2e0ca27f1c490d8eb18c5ca [file] [log] [blame]
Andrzej Zaborowski7a635ea2011-03-28 12:56:33 +00001/*
2 * Ethernet interface part of the LG VL600 LTE modem (4G dongle)
3 *
4 * Copyright (C) 2011 Intel Corporation
5 * Author: Andrzej Zaborowski <balrogg@gmail.com>
6 *
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.
11 *
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.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21#include <linux/etherdevice.h>
22#include <linux/ethtool.h>
23#include <linux/mii.h>
24#include <linux/usb.h>
25#include <linux/usb/cdc.h>
26#include <linux/usb/usbnet.h>
27#include <linux/if_ether.h>
28#include <linux/if_arp.h>
29#include <linux/inetdevice.h>
30
31/*
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.
37 *
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.
47 */
48
49struct vl600_frame_hdr {
50 __le32 len;
51 __le32 serial;
52 __le32 pkt_cnt;
53 __le32 dummy_flags;
54 __le32 dummy;
55 __le32 magic;
56} __attribute__((packed));
57
58struct vl600_pkt_hdr {
59 __le32 dummy[2];
60 __le32 len;
61 __be16 h_proto;
62} __attribute__((packed));
63
64struct vl600_state {
65 struct sk_buff *current_rx_buf;
66};
67
68static int vl600_bind(struct usbnet *dev, struct usb_interface *intf)
69{
70 int ret;
71 struct vl600_state *s = kzalloc(sizeof(struct vl600_state), GFP_KERNEL);
72
73 if (!s)
74 return -ENOMEM;
75
76 ret = usbnet_cdc_bind(dev, intf);
77 if (ret) {
78 kfree(s);
79 return ret;
80 }
81
82 dev->driver_priv = s;
83
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
93 return ret;
94}
95
96static void vl600_unbind(struct usbnet *dev, struct usb_interface *intf)
97{
98 struct vl600_state *s = dev->driver_priv;
99
100 if (s->current_rx_buf)
101 dev_kfree_skb(s->current_rx_buf);
102
103 kfree(s);
104
105 return usbnet_cdc_unbind(dev, intf);
106}
107
108static int vl600_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
109{
110 struct vl600_frame_hdr *frame;
111 struct vl600_pkt_hdr *packet;
112 struct ethhdr *ethhdr;
113 int packet_len, count;
114 struct sk_buff *buf = skb;
115 struct sk_buff *clone;
116 struct vl600_state *s = dev->driver_priv;
117
118 /* Frame lengths are generally 4B multiplies but every couple of
119 * hours there's an odd number of bytes sized yet correct frame,
120 * so don't require this. */
121
122 /* Allow a packet (or multiple packets batched together) to be
123 * split across many frames. We don't allow a new batch to
124 * begin in the same frame another one is ending however, and no
125 * leading or trailing pad bytes. */
126 if (s->current_rx_buf) {
127 frame = (struct vl600_frame_hdr *) s->current_rx_buf->data;
128 if (skb->len + s->current_rx_buf->len >
129 le32_to_cpup(&frame->len)) {
130 netif_err(dev, ifup, dev->net, "Fragment too long\n");
131 dev->net->stats.rx_length_errors++;
132 goto error;
133 }
134
135 buf = s->current_rx_buf;
136 memcpy(skb_put(buf, skb->len), skb->data, skb->len);
137 } else if (skb->len < 4) {
138 netif_err(dev, ifup, dev->net, "Frame too short\n");
139 dev->net->stats.rx_length_errors++;
140 goto error;
141 }
142
143 frame = (struct vl600_frame_hdr *) buf->data;
144 /* NOTE: Should check that frame->magic == 0x53544448?
145 * Otherwise if we receive garbage at the beginning of the frame
146 * we may end up allocating a huge buffer and saving all the
147 * future incoming data into it. */
148
149 if (buf->len < sizeof(*frame) ||
150 buf->len != le32_to_cpup(&frame->len)) {
151 /* Save this fragment for later assembly */
152 if (s->current_rx_buf)
153 return 0;
154
155 s->current_rx_buf = skb_copy_expand(skb, 0,
156 le32_to_cpup(&frame->len), GFP_ATOMIC);
157 if (!s->current_rx_buf) {
158 netif_err(dev, ifup, dev->net, "Reserving %i bytes "
159 "for packet assembly failed.\n",
160 le32_to_cpup(&frame->len));
161 dev->net->stats.rx_errors++;
162 }
163
164 return 0;
165 }
166
167 count = le32_to_cpup(&frame->pkt_cnt);
168
169 skb_pull(buf, sizeof(*frame));
170
171 while (count--) {
172 if (buf->len < sizeof(*packet)) {
173 netif_err(dev, ifup, dev->net, "Packet too short\n");
174 goto error;
175 }
176
177 packet = (struct vl600_pkt_hdr *) buf->data;
178 packet_len = sizeof(*packet) + le32_to_cpup(&packet->len);
179 if (packet_len > buf->len) {
180 netif_err(dev, ifup, dev->net,
181 "Bad packet length stored in header\n");
182 goto error;
183 }
184
185 /* Packet header is same size as the ethernet header
186 * (sizeof(*packet) == sizeof(*ethhdr)), additionally
187 * the h_proto field is in the same place so we just leave it
188 * alone and fill in the remaining fields.
189 */
190 ethhdr = (struct ethhdr *) skb->data;
191 if (be16_to_cpup(&ethhdr->h_proto) == ETH_P_ARP &&
192 buf->len > 0x26) {
193 /* Copy the addresses from packet contents */
194 memcpy(ethhdr->h_source,
195 &buf->data[sizeof(*ethhdr) + 0x8],
196 ETH_ALEN);
197 memcpy(ethhdr->h_dest,
198 &buf->data[sizeof(*ethhdr) + 0x12],
199 ETH_ALEN);
200 } else {
201 memset(ethhdr->h_source, 0, ETH_ALEN);
202 memcpy(ethhdr->h_dest, dev->net->dev_addr, ETH_ALEN);
203 }
204
205 if (count) {
206 /* Not the last packet in this batch */
207 clone = skb_clone(buf, GFP_ATOMIC);
208 if (!clone)
209 goto error;
210
211 skb_trim(clone, packet_len);
212 usbnet_skb_return(dev, clone);
213
214 skb_pull(buf, (packet_len + 3) & ~3);
215 } else {
216 skb_trim(buf, packet_len);
217
218 if (s->current_rx_buf) {
219 usbnet_skb_return(dev, buf);
220 s->current_rx_buf = NULL;
221 return 0;
222 }
223
224 return 1;
225 }
226 }
227
228error:
229 if (s->current_rx_buf) {
230 dev_kfree_skb_any(s->current_rx_buf);
231 s->current_rx_buf = NULL;
232 }
233 dev->net->stats.rx_errors++;
234 return 0;
235}
236
237static struct sk_buff *vl600_tx_fixup(struct usbnet *dev,
238 struct sk_buff *skb, gfp_t flags)
239{
240 struct sk_buff *ret;
241 struct vl600_frame_hdr *frame;
242 struct vl600_pkt_hdr *packet;
243 static uint32_t serial = 1;
244 int orig_len = skb->len - sizeof(struct ethhdr);
245 int full_len = (skb->len + sizeof(struct vl600_frame_hdr) + 3) & ~3;
246
247 frame = (struct vl600_frame_hdr *) skb->data;
248 if (skb->len > sizeof(*frame) && skb->len == le32_to_cpup(&frame->len))
249 return skb; /* Already encapsulated? */
250
251 if (skb->len < sizeof(struct ethhdr))
252 /* Drop, device can only deal with ethernet packets */
253 return NULL;
254
255 if (!skb_cloned(skb)) {
256 int headroom = skb_headroom(skb);
257 int tailroom = skb_tailroom(skb);
258
259 if (tailroom >= full_len - skb->len - sizeof(*frame) &&
260 headroom >= sizeof(*frame))
261 /* There's enough head and tail room */
262 goto encapsulate;
263
264 if (headroom + tailroom + skb->len >= full_len) {
265 /* There's enough total room, just readjust */
266 skb->data = memmove(skb->head + sizeof(*frame),
267 skb->data, skb->len);
268 skb_set_tail_pointer(skb, skb->len);
269 goto encapsulate;
270 }
271 }
272
273 /* Alloc a new skb with the required size */
274 ret = skb_copy_expand(skb, sizeof(struct vl600_frame_hdr), full_len -
275 skb->len - sizeof(struct vl600_frame_hdr), flags);
276 dev_kfree_skb_any(skb);
277 if (!ret)
278 return ret;
279 skb = ret;
280
281encapsulate:
282 /* Packet header is same size as ethernet packet header
283 * (sizeof(*packet) == sizeof(struct ethhdr)), additionally the
284 * h_proto field is in the same place so we just leave it alone and
285 * overwrite the remaining fields.
286 */
287 packet = (struct vl600_pkt_hdr *) skb->data;
288 memset(&packet->dummy, 0, sizeof(packet->dummy));
289 packet->len = cpu_to_le32(orig_len);
290
291 frame = (struct vl600_frame_hdr *) skb_push(skb, sizeof(*frame));
292 memset(frame, 0, sizeof(*frame));
293 frame->len = cpu_to_le32(full_len);
294 frame->serial = cpu_to_le32(serial++);
295 frame->pkt_cnt = cpu_to_le32(1);
296
297 if (skb->len < full_len) /* Pad */
298 skb_put(skb, full_len - skb->len);
299
300 return skb;
301}
302
303static const struct driver_info vl600_info = {
304 .description = "LG VL600 modem",
305 .flags = FLAG_ETHER | FLAG_RX_ASSEMBLE,
306 .bind = vl600_bind,
307 .unbind = vl600_unbind,
308 .status = usbnet_cdc_status,
309 .rx_fixup = vl600_rx_fixup,
310 .tx_fixup = vl600_tx_fixup,
311};
312
313static const struct usb_device_id products[] = {
314 {
315 USB_DEVICE_AND_INTERFACE_INFO(0x1004, 0x61aa, USB_CLASS_COMM,
316 USB_CDC_SUBCLASS_ETHERNET, USB_CDC_PROTO_NONE),
317 .driver_info = (unsigned long) &vl600_info,
318 },
319 {}, /* End */
320};
321MODULE_DEVICE_TABLE(usb, products);
322
323static struct usb_driver lg_vl600_driver = {
324 .name = "lg-vl600",
325 .id_table = products,
326 .probe = usbnet_probe,
327 .disconnect = usbnet_disconnect,
328 .suspend = usbnet_suspend,
329 .resume = usbnet_resume,
330};
331
332static int __init vl600_init(void)
333{
334 return usb_register(&lg_vl600_driver);
335}
336module_init(vl600_init);
337
338static void __exit vl600_exit(void)
339{
340 usb_deregister(&lg_vl600_driver);
341}
342module_exit(vl600_exit);
343
344MODULE_AUTHOR("Anrzej Zaborowski");
345MODULE_DESCRIPTION("LG-VL600 modem's ethernet link");
346MODULE_LICENSE("GPL");