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Linux/drivers/net/usb/cdc_mbim.c

  1 /*
  2  * Copyright (c) 2012  Smith Micro Software, Inc.
  3  * Copyright (c) 2012  Bjørn Mork <bjorn@mork.no>
  4  *
  5  * This driver is based on and reuse most of cdc_ncm, which is
  6  * Copyright (C) ST-Ericsson 2010-2012
  7  *
  8  * This program is free software; you can redistribute it and/or
  9  * modify it under the terms of the GNU General Public License
 10  * version 2 as published by the Free Software Foundation.
 11  */
 12 
 13 #include <linux/module.h>
 14 #include <linux/netdevice.h>
 15 #include <linux/ethtool.h>
 16 #include <linux/if_vlan.h>
 17 #include <linux/ip.h>
 18 #include <linux/mii.h>
 19 #include <linux/usb.h>
 20 #include <linux/usb/cdc.h>
 21 #include <linux/usb/usbnet.h>
 22 #include <linux/usb/cdc-wdm.h>
 23 #include <linux/usb/cdc_ncm.h>
 24 #include <net/ipv6.h>
 25 #include <net/addrconf.h>
 26 
 27 /* driver specific data - must match cdc_ncm usage */
 28 struct cdc_mbim_state {
 29         struct cdc_ncm_ctx *ctx;
 30         atomic_t pmcount;
 31         struct usb_driver *subdriver;
 32         struct usb_interface *control;
 33         struct usb_interface *data;
 34 };
 35 
 36 /* using a counter to merge subdriver requests with our own into a combined state */
 37 static int cdc_mbim_manage_power(struct usbnet *dev, int on)
 38 {
 39         struct cdc_mbim_state *info = (void *)&dev->data;
 40         int rv = 0;
 41 
 42         dev_dbg(&dev->intf->dev, "%s() pmcount=%d, on=%d\n", __func__, atomic_read(&info->pmcount), on);
 43 
 44         if ((on && atomic_add_return(1, &info->pmcount) == 1) || (!on && atomic_dec_and_test(&info->pmcount))) {
 45                 /* need autopm_get/put here to ensure the usbcore sees the new value */
 46                 rv = usb_autopm_get_interface(dev->intf);
 47                 dev->intf->needs_remote_wakeup = on;
 48                 if (!rv)
 49                         usb_autopm_put_interface(dev->intf);
 50         }
 51         return 0;
 52 }
 53 
 54 static int cdc_mbim_wdm_manage_power(struct usb_interface *intf, int status)
 55 {
 56         struct usbnet *dev = usb_get_intfdata(intf);
 57 
 58         /* can be called while disconnecting */
 59         if (!dev)
 60                 return 0;
 61 
 62         return cdc_mbim_manage_power(dev, status);
 63 }
 64 
 65 
 66 static int cdc_mbim_bind(struct usbnet *dev, struct usb_interface *intf)
 67 {
 68         struct cdc_ncm_ctx *ctx;
 69         struct usb_driver *subdriver = ERR_PTR(-ENODEV);
 70         int ret = -ENODEV;
 71         u8 data_altsetting = cdc_ncm_select_altsetting(dev, intf);
 72         struct cdc_mbim_state *info = (void *)&dev->data;
 73 
 74         /* Probably NCM, defer for cdc_ncm_bind */
 75         if (!cdc_ncm_comm_intf_is_mbim(intf->cur_altsetting))
 76                 goto err;
 77 
 78         ret = cdc_ncm_bind_common(dev, intf, data_altsetting);
 79         if (ret)
 80                 goto err;
 81 
 82         ctx = info->ctx;
 83 
 84         /* The MBIM descriptor and the status endpoint are required */
 85         if (ctx->mbim_desc && dev->status)
 86                 subdriver = usb_cdc_wdm_register(ctx->control,
 87                                                  &dev->status->desc,
 88                                                  le16_to_cpu(ctx->mbim_desc->wMaxControlMessage),
 89                                                  cdc_mbim_wdm_manage_power);
 90         if (IS_ERR(subdriver)) {
 91                 ret = PTR_ERR(subdriver);
 92                 cdc_ncm_unbind(dev, intf);
 93                 goto err;
 94         }
 95 
 96         /* can't let usbnet use the interrupt endpoint */
 97         dev->status = NULL;
 98         info->subdriver = subdriver;
 99 
100         /* MBIM cannot do ARP */
101         dev->net->flags |= IFF_NOARP;
102 
103         /* no need to put the VLAN tci in the packet headers */
104         dev->net->features |= NETIF_F_HW_VLAN_CTAG_TX;
105 err:
106         return ret;
107 }
108 
109 static void cdc_mbim_unbind(struct usbnet *dev, struct usb_interface *intf)
110 {
111         struct cdc_mbim_state *info = (void *)&dev->data;
112         struct cdc_ncm_ctx *ctx = info->ctx;
113 
114         /* disconnect subdriver from control interface */
115         if (info->subdriver && info->subdriver->disconnect)
116                 info->subdriver->disconnect(ctx->control);
117         info->subdriver = NULL;
118 
119         /* let NCM unbind clean up both control and data interface */
120         cdc_ncm_unbind(dev, intf);
121 }
122 
123 
124 static struct sk_buff *cdc_mbim_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
125 {
126         struct sk_buff *skb_out;
127         struct cdc_mbim_state *info = (void *)&dev->data;
128         struct cdc_ncm_ctx *ctx = info->ctx;
129         __le32 sign = cpu_to_le32(USB_CDC_MBIM_NDP16_IPS_SIGN);
130         u16 tci = 0;
131         u8 *c;
132 
133         if (!ctx)
134                 goto error;
135 
136         if (skb) {
137                 if (skb->len <= ETH_HLEN)
138                         goto error;
139 
140                 /* mapping VLANs to MBIM sessions:
141                  *   no tag     => IPS session <0>
142                  *   1 - 255    => IPS session <vlanid>
143                  *   256 - 511  => DSS session <vlanid - 256>
144                  *   512 - 4095 => unsupported, drop
145                  */
146                 vlan_get_tag(skb, &tci);
147 
148                 switch (tci & 0x0f00) {
149                 case 0x0000: /* VLAN ID 0 - 255 */
150                         /* verify that datagram is IPv4 or IPv6 */
151                         skb_reset_mac_header(skb);
152                         switch (eth_hdr(skb)->h_proto) {
153                         case htons(ETH_P_IP):
154                         case htons(ETH_P_IPV6):
155                                 break;
156                         default:
157                                 goto error;
158                         }
159                         c = (u8 *)&sign;
160                         c[3] = tci;
161                         break;
162                 case 0x0100: /* VLAN ID 256 - 511 */
163                         sign = cpu_to_le32(USB_CDC_MBIM_NDP16_DSS_SIGN);
164                         c = (u8 *)&sign;
165                         c[3] = tci;
166                         break;
167                 default:
168                         netif_err(dev, tx_err, dev->net,
169                                   "unsupported tci=0x%04x\n", tci);
170                         goto error;
171                 }
172                 skb_pull(skb, ETH_HLEN);
173         }
174 
175         spin_lock_bh(&ctx->mtx);
176         skb_out = cdc_ncm_fill_tx_frame(dev, skb, sign);
177         spin_unlock_bh(&ctx->mtx);
178         return skb_out;
179 
180 error:
181         if (skb)
182                 dev_kfree_skb_any(skb);
183 
184         return NULL;
185 }
186 
187 /* Some devices are known to send Neigbor Solicitation messages and
188  * require Neigbor Advertisement replies.  The IPv6 core will not
189  * respond since IFF_NOARP is set, so we must handle them ourselves.
190  */
191 static void do_neigh_solicit(struct usbnet *dev, u8 *buf, u16 tci)
192 {
193         struct ipv6hdr *iph = (void *)buf;
194         struct nd_msg *msg = (void *)(iph + 1);
195         struct net_device *netdev;
196         struct inet6_dev *in6_dev;
197         bool is_router;
198 
199         /* we'll only respond to requests from unicast addresses to
200          * our solicited node addresses.
201          */
202         if (!ipv6_addr_is_solict_mult(&iph->daddr) ||
203             !(ipv6_addr_type(&iph->saddr) & IPV6_ADDR_UNICAST))
204                 return;
205 
206         /* need to send the NA on the VLAN dev, if any */
207         if (tci)
208                 netdev = __vlan_find_dev_deep(dev->net, htons(ETH_P_8021Q),
209                                               tci);
210         else
211                 netdev = dev->net;
212         if (!netdev)
213                 return;
214 
215         in6_dev = in6_dev_get(netdev);
216         if (!in6_dev)
217                 return;
218         is_router = !!in6_dev->cnf.forwarding;
219         in6_dev_put(in6_dev);
220 
221         /* ipv6_stub != NULL if in6_dev_get returned an inet6_dev */
222         ipv6_stub->ndisc_send_na(netdev, NULL, &iph->saddr, &msg->target,
223                                  is_router /* router */,
224                                  true /* solicited */,
225                                  false /* override */,
226                                  true /* inc_opt */);
227 }
228 
229 static bool is_neigh_solicit(u8 *buf, size_t len)
230 {
231         struct ipv6hdr *iph = (void *)buf;
232         struct nd_msg *msg = (void *)(iph + 1);
233 
234         return (len >= sizeof(struct ipv6hdr) + sizeof(struct nd_msg) &&
235                 iph->nexthdr == IPPROTO_ICMPV6 &&
236                 msg->icmph.icmp6_code == 0 &&
237                 msg->icmph.icmp6_type == NDISC_NEIGHBOUR_SOLICITATION);
238 }
239 
240 
241 static struct sk_buff *cdc_mbim_process_dgram(struct usbnet *dev, u8 *buf, size_t len, u16 tci)
242 {
243         __be16 proto = htons(ETH_P_802_3);
244         struct sk_buff *skb = NULL;
245 
246         if (tci < 256) { /* IPS session? */
247                 if (len < sizeof(struct iphdr))
248                         goto err;
249 
250                 switch (*buf & 0xf0) {
251                 case 0x40:
252                         proto = htons(ETH_P_IP);
253                         break;
254                 case 0x60:
255                         if (is_neigh_solicit(buf, len))
256                                 do_neigh_solicit(dev, buf, tci);
257                         proto = htons(ETH_P_IPV6);
258                         break;
259                 default:
260                         goto err;
261                 }
262         }
263 
264         skb = netdev_alloc_skb_ip_align(dev->net,  len + ETH_HLEN);
265         if (!skb)
266                 goto err;
267 
268         /* add an ethernet header */
269         skb_put(skb, ETH_HLEN);
270         skb_reset_mac_header(skb);
271         eth_hdr(skb)->h_proto = proto;
272         memset(eth_hdr(skb)->h_source, 0, ETH_ALEN);
273         memcpy(eth_hdr(skb)->h_dest, dev->net->dev_addr, ETH_ALEN);
274 
275         /* add datagram */
276         memcpy(skb_put(skb, len), buf, len);
277 
278         /* map MBIM session to VLAN */
279         if (tci)
280                 vlan_put_tag(skb, htons(ETH_P_8021Q), tci);
281 err:
282         return skb;
283 }
284 
285 static int cdc_mbim_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in)
286 {
287         struct sk_buff *skb;
288         struct cdc_mbim_state *info = (void *)&dev->data;
289         struct cdc_ncm_ctx *ctx = info->ctx;
290         int len;
291         int nframes;
292         int x;
293         int offset;
294         struct usb_cdc_ncm_ndp16 *ndp16;
295         struct usb_cdc_ncm_dpe16 *dpe16;
296         int ndpoffset;
297         int loopcount = 50; /* arbitrary max preventing infinite loop */
298         u8 *c;
299         u16 tci;
300 
301         ndpoffset = cdc_ncm_rx_verify_nth16(ctx, skb_in);
302         if (ndpoffset < 0)
303                 goto error;
304 
305 next_ndp:
306         nframes = cdc_ncm_rx_verify_ndp16(skb_in, ndpoffset);
307         if (nframes < 0)
308                 goto error;
309 
310         ndp16 = (struct usb_cdc_ncm_ndp16 *)(skb_in->data + ndpoffset);
311 
312         switch (ndp16->dwSignature & cpu_to_le32(0x00ffffff)) {
313         case cpu_to_le32(USB_CDC_MBIM_NDP16_IPS_SIGN):
314                 c = (u8 *)&ndp16->dwSignature;
315                 tci = c[3];
316                 break;
317         case cpu_to_le32(USB_CDC_MBIM_NDP16_DSS_SIGN):
318                 c = (u8 *)&ndp16->dwSignature;
319                 tci = c[3] + 256;
320                 break;
321         default:
322                 netif_dbg(dev, rx_err, dev->net,
323                           "unsupported NDP signature <0x%08x>\n",
324                           le32_to_cpu(ndp16->dwSignature));
325                 goto err_ndp;
326 
327         }
328 
329         dpe16 = ndp16->dpe16;
330         for (x = 0; x < nframes; x++, dpe16++) {
331                 offset = le16_to_cpu(dpe16->wDatagramIndex);
332                 len = le16_to_cpu(dpe16->wDatagramLength);
333 
334                 /*
335                  * CDC NCM ch. 3.7
336                  * All entries after first NULL entry are to be ignored
337                  */
338                 if ((offset == 0) || (len == 0)) {
339                         if (!x)
340                                 goto err_ndp; /* empty NTB */
341                         break;
342                 }
343 
344                 /* sanity checking */
345                 if (((offset + len) > skb_in->len) || (len > ctx->rx_max)) {
346                         netif_dbg(dev, rx_err, dev->net,
347                                   "invalid frame detected (ignored) offset[%u]=%u, length=%u, skb=%p\n",
348                                   x, offset, len, skb_in);
349                         if (!x)
350                                 goto err_ndp;
351                         break;
352                 } else {
353                         skb = cdc_mbim_process_dgram(dev, skb_in->data + offset, len, tci);
354                         if (!skb)
355                                 goto error;
356                         usbnet_skb_return(dev, skb);
357                 }
358         }
359 err_ndp:
360         /* are there more NDPs to process? */
361         ndpoffset = le16_to_cpu(ndp16->wNextNdpIndex);
362         if (ndpoffset && loopcount--)
363                 goto next_ndp;
364 
365         return 1;
366 error:
367         return 0;
368 }
369 
370 static int cdc_mbim_suspend(struct usb_interface *intf, pm_message_t message)
371 {
372         int ret = -ENODEV;
373         struct usbnet *dev = usb_get_intfdata(intf);
374         struct cdc_mbim_state *info = (void *)&dev->data;
375         struct cdc_ncm_ctx *ctx = info->ctx;
376 
377         if (!ctx)
378                 goto error;
379 
380         /*
381          * Both usbnet_suspend() and subdriver->suspend() MUST return 0
382          * in system sleep context, otherwise, the resume callback has
383          * to recover device from previous suspend failure.
384          */
385         ret = usbnet_suspend(intf, message);
386         if (ret < 0)
387                 goto error;
388 
389         if (intf == ctx->control && info->subdriver && info->subdriver->suspend)
390                 ret = info->subdriver->suspend(intf, message);
391         if (ret < 0)
392                 usbnet_resume(intf);
393 
394 error:
395         return ret;
396 }
397 
398 static int cdc_mbim_resume(struct usb_interface *intf)
399 {
400         int  ret = 0;
401         struct usbnet *dev = usb_get_intfdata(intf);
402         struct cdc_mbim_state *info = (void *)&dev->data;
403         struct cdc_ncm_ctx *ctx = info->ctx;
404         bool callsub = (intf == ctx->control && info->subdriver && info->subdriver->resume);
405 
406         if (callsub)
407                 ret = info->subdriver->resume(intf);
408         if (ret < 0)
409                 goto err;
410         ret = usbnet_resume(intf);
411         if (ret < 0 && callsub)
412                 info->subdriver->suspend(intf, PMSG_SUSPEND);
413 err:
414         return ret;
415 }
416 
417 static const struct driver_info cdc_mbim_info = {
418         .description = "CDC MBIM",
419         .flags = FLAG_NO_SETINT | FLAG_MULTI_PACKET | FLAG_WWAN,
420         .bind = cdc_mbim_bind,
421         .unbind = cdc_mbim_unbind,
422         .manage_power = cdc_mbim_manage_power,
423         .rx_fixup = cdc_mbim_rx_fixup,
424         .tx_fixup = cdc_mbim_tx_fixup,
425 };
426 
427 /* MBIM and NCM devices should not need a ZLP after NTBs with
428  * dwNtbOutMaxSize length. Nevertheless, a number of devices from
429  * different vendor IDs will fail unless we send ZLPs, forcing us
430  * to make this the default.
431  *
432  * This default may cause a performance penalty for spec conforming
433  * devices wanting to take advantage of optimizations possible without
434  * ZLPs.  A whitelist is added in an attempt to avoid this for devices
435  * known to conform to the MBIM specification.
436  *
437  * All known devices supporting NCM compatibility mode are also
438  * conforming to the NCM and MBIM specifications. For this reason, the
439  * NCM subclass entry is also in the ZLP whitelist.
440  */
441 static const struct driver_info cdc_mbim_info_zlp = {
442         .description = "CDC MBIM",
443         .flags = FLAG_NO_SETINT | FLAG_MULTI_PACKET | FLAG_WWAN | FLAG_SEND_ZLP,
444         .bind = cdc_mbim_bind,
445         .unbind = cdc_mbim_unbind,
446         .manage_power = cdc_mbim_manage_power,
447         .rx_fixup = cdc_mbim_rx_fixup,
448         .tx_fixup = cdc_mbim_tx_fixup,
449 };
450 
451 static const struct usb_device_id mbim_devs[] = {
452         /* This duplicate NCM entry is intentional. MBIM devices can
453          * be disguised as NCM by default, and this is necessary to
454          * allow us to bind the correct driver_info to such devices.
455          *
456          * bind() will sort out this for us, selecting the correct
457          * entry and reject the other
458          */
459         { USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
460           .driver_info = (unsigned long)&cdc_mbim_info,
461         },
462         /* ZLP conformance whitelist: All Ericsson MBIM devices */
463         { USB_VENDOR_AND_INTERFACE_INFO(0x0bdb, USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
464           .driver_info = (unsigned long)&cdc_mbim_info,
465         },
466         /* default entry */
467         { USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
468           .driver_info = (unsigned long)&cdc_mbim_info_zlp,
469         },
470         {
471         },
472 };
473 MODULE_DEVICE_TABLE(usb, mbim_devs);
474 
475 static struct usb_driver cdc_mbim_driver = {
476         .name = "cdc_mbim",
477         .id_table = mbim_devs,
478         .probe = usbnet_probe,
479         .disconnect = usbnet_disconnect,
480         .suspend = cdc_mbim_suspend,
481         .resume = cdc_mbim_resume,
482         .reset_resume = cdc_mbim_resume,
483         .supports_autosuspend = 1,
484         .disable_hub_initiated_lpm = 1,
485 };
486 module_usb_driver(cdc_mbim_driver);
487 
488 MODULE_AUTHOR("Greg Suarez <gsuarez@smithmicro.com>");
489 MODULE_AUTHOR("Bjørn Mork <bjorn@mork.no>");
490 MODULE_DESCRIPTION("USB CDC MBIM host driver");
491 MODULE_LICENSE("GPL");
492 

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