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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 /* verify that the ethernet protocol is IPv4 or IPv6 */
124 static bool is_ip_proto(__be16 proto)
125 {
126         switch (proto) {
127         case htons(ETH_P_IP):
128         case htons(ETH_P_IPV6):
129                 return true;
130         }
131         return false;
132 }
133 
134 static struct sk_buff *cdc_mbim_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
135 {
136         struct sk_buff *skb_out;
137         struct cdc_mbim_state *info = (void *)&dev->data;
138         struct cdc_ncm_ctx *ctx = info->ctx;
139         __le32 sign = cpu_to_le32(USB_CDC_MBIM_NDP16_IPS_SIGN);
140         u16 tci = 0;
141         bool is_ip;
142         u8 *c;
143 
144         if (!ctx)
145                 goto error;
146 
147         if (skb) {
148                 if (skb->len <= ETH_HLEN)
149                         goto error;
150 
151                 /* Some applications using e.g. packet sockets will
152                  * bypass the VLAN acceleration and create tagged
153                  * ethernet frames directly.  We primarily look for
154                  * the accelerated out-of-band tag, but fall back if
155                  * required
156                  */
157                 skb_reset_mac_header(skb);
158                 if (vlan_get_tag(skb, &tci) < 0 && skb->len > VLAN_ETH_HLEN &&
159                     __vlan_get_tag(skb, &tci) == 0) {
160                         is_ip = is_ip_proto(vlan_eth_hdr(skb)->h_vlan_encapsulated_proto);
161                         skb_pull(skb, VLAN_ETH_HLEN);
162                 } else {
163                         is_ip = is_ip_proto(eth_hdr(skb)->h_proto);
164                         skb_pull(skb, ETH_HLEN);
165                 }
166 
167                 /* mapping VLANs to MBIM sessions:
168                  *   no tag     => IPS session <0>
169                  *   1 - 255    => IPS session <vlanid>
170                  *   256 - 511  => DSS session <vlanid - 256>
171                  *   512 - 4095 => unsupported, drop
172                  */
173                 switch (tci & 0x0f00) {
174                 case 0x0000: /* VLAN ID 0 - 255 */
175                         if (!is_ip)
176                                 goto error;
177                         c = (u8 *)&sign;
178                         c[3] = tci;
179                         break;
180                 case 0x0100: /* VLAN ID 256 - 511 */
181                         sign = cpu_to_le32(USB_CDC_MBIM_NDP16_DSS_SIGN);
182                         c = (u8 *)&sign;
183                         c[3] = tci;
184                         break;
185                 default:
186                         netif_err(dev, tx_err, dev->net,
187                                   "unsupported tci=0x%04x\n", tci);
188                         goto error;
189                 }
190         }
191 
192         spin_lock_bh(&ctx->mtx);
193         skb_out = cdc_ncm_fill_tx_frame(dev, skb, sign);
194         spin_unlock_bh(&ctx->mtx);
195         return skb_out;
196 
197 error:
198         if (skb)
199                 dev_kfree_skb_any(skb);
200 
201         return NULL;
202 }
203 
204 /* Some devices are known to send Neigbor Solicitation messages and
205  * require Neigbor Advertisement replies.  The IPv6 core will not
206  * respond since IFF_NOARP is set, so we must handle them ourselves.
207  */
208 static void do_neigh_solicit(struct usbnet *dev, u8 *buf, u16 tci)
209 {
210         struct ipv6hdr *iph = (void *)buf;
211         struct nd_msg *msg = (void *)(iph + 1);
212         struct net_device *netdev;
213         struct inet6_dev *in6_dev;
214         bool is_router;
215 
216         /* we'll only respond to requests from unicast addresses to
217          * our solicited node addresses.
218          */
219         if (!ipv6_addr_is_solict_mult(&iph->daddr) ||
220             !(ipv6_addr_type(&iph->saddr) & IPV6_ADDR_UNICAST))
221                 return;
222 
223         /* need to send the NA on the VLAN dev, if any */
224         rcu_read_lock();
225         if (tci) {
226                 netdev = __vlan_find_dev_deep(dev->net, htons(ETH_P_8021Q),
227                                               tci);
228                 if (!netdev) {
229                         rcu_read_unlock();
230                         return;
231                 }
232         } else {
233                 netdev = dev->net;
234         }
235         dev_hold(netdev);
236         rcu_read_unlock();
237 
238         in6_dev = in6_dev_get(netdev);
239         if (!in6_dev)
240                 goto out;
241         is_router = !!in6_dev->cnf.forwarding;
242         in6_dev_put(in6_dev);
243 
244         /* ipv6_stub != NULL if in6_dev_get returned an inet6_dev */
245         ipv6_stub->ndisc_send_na(netdev, NULL, &iph->saddr, &msg->target,
246                                  is_router /* router */,
247                                  true /* solicited */,
248                                  false /* override */,
249                                  true /* inc_opt */);
250 out:
251         dev_put(netdev);
252 }
253 
254 static bool is_neigh_solicit(u8 *buf, size_t len)
255 {
256         struct ipv6hdr *iph = (void *)buf;
257         struct nd_msg *msg = (void *)(iph + 1);
258 
259         return (len >= sizeof(struct ipv6hdr) + sizeof(struct nd_msg) &&
260                 iph->nexthdr == IPPROTO_ICMPV6 &&
261                 msg->icmph.icmp6_code == 0 &&
262                 msg->icmph.icmp6_type == NDISC_NEIGHBOUR_SOLICITATION);
263 }
264 
265 
266 static struct sk_buff *cdc_mbim_process_dgram(struct usbnet *dev, u8 *buf, size_t len, u16 tci)
267 {
268         __be16 proto = htons(ETH_P_802_3);
269         struct sk_buff *skb = NULL;
270 
271         if (tci < 256) { /* IPS session? */
272                 if (len < sizeof(struct iphdr))
273                         goto err;
274 
275                 switch (*buf & 0xf0) {
276                 case 0x40:
277                         proto = htons(ETH_P_IP);
278                         break;
279                 case 0x60:
280                         if (is_neigh_solicit(buf, len))
281                                 do_neigh_solicit(dev, buf, tci);
282                         proto = htons(ETH_P_IPV6);
283                         break;
284                 default:
285                         goto err;
286                 }
287         }
288 
289         skb = netdev_alloc_skb_ip_align(dev->net,  len + ETH_HLEN);
290         if (!skb)
291                 goto err;
292 
293         /* add an ethernet header */
294         skb_put(skb, ETH_HLEN);
295         skb_reset_mac_header(skb);
296         eth_hdr(skb)->h_proto = proto;
297         memset(eth_hdr(skb)->h_source, 0, ETH_ALEN);
298         memcpy(eth_hdr(skb)->h_dest, dev->net->dev_addr, ETH_ALEN);
299 
300         /* add datagram */
301         memcpy(skb_put(skb, len), buf, len);
302 
303         /* map MBIM session to VLAN */
304         if (tci)
305                 vlan_put_tag(skb, htons(ETH_P_8021Q), tci);
306 err:
307         return skb;
308 }
309 
310 static int cdc_mbim_rx_fixup(struct usbnet *dev, struct sk_buff *skb_in)
311 {
312         struct sk_buff *skb;
313         struct cdc_mbim_state *info = (void *)&dev->data;
314         struct cdc_ncm_ctx *ctx = info->ctx;
315         int len;
316         int nframes;
317         int x;
318         int offset;
319         struct usb_cdc_ncm_ndp16 *ndp16;
320         struct usb_cdc_ncm_dpe16 *dpe16;
321         int ndpoffset;
322         int loopcount = 50; /* arbitrary max preventing infinite loop */
323         u8 *c;
324         u16 tci;
325 
326         ndpoffset = cdc_ncm_rx_verify_nth16(ctx, skb_in);
327         if (ndpoffset < 0)
328                 goto error;
329 
330 next_ndp:
331         nframes = cdc_ncm_rx_verify_ndp16(skb_in, ndpoffset);
332         if (nframes < 0)
333                 goto error;
334 
335         ndp16 = (struct usb_cdc_ncm_ndp16 *)(skb_in->data + ndpoffset);
336 
337         switch (ndp16->dwSignature & cpu_to_le32(0x00ffffff)) {
338         case cpu_to_le32(USB_CDC_MBIM_NDP16_IPS_SIGN):
339                 c = (u8 *)&ndp16->dwSignature;
340                 tci = c[3];
341                 break;
342         case cpu_to_le32(USB_CDC_MBIM_NDP16_DSS_SIGN):
343                 c = (u8 *)&ndp16->dwSignature;
344                 tci = c[3] + 256;
345                 break;
346         default:
347                 netif_dbg(dev, rx_err, dev->net,
348                           "unsupported NDP signature <0x%08x>\n",
349                           le32_to_cpu(ndp16->dwSignature));
350                 goto err_ndp;
351 
352         }
353 
354         dpe16 = ndp16->dpe16;
355         for (x = 0; x < nframes; x++, dpe16++) {
356                 offset = le16_to_cpu(dpe16->wDatagramIndex);
357                 len = le16_to_cpu(dpe16->wDatagramLength);
358 
359                 /*
360                  * CDC NCM ch. 3.7
361                  * All entries after first NULL entry are to be ignored
362                  */
363                 if ((offset == 0) || (len == 0)) {
364                         if (!x)
365                                 goto err_ndp; /* empty NTB */
366                         break;
367                 }
368 
369                 /* sanity checking */
370                 if (((offset + len) > skb_in->len) || (len > ctx->rx_max)) {
371                         netif_dbg(dev, rx_err, dev->net,
372                                   "invalid frame detected (ignored) offset[%u]=%u, length=%u, skb=%p\n",
373                                   x, offset, len, skb_in);
374                         if (!x)
375                                 goto err_ndp;
376                         break;
377                 } else {
378                         skb = cdc_mbim_process_dgram(dev, skb_in->data + offset, len, tci);
379                         if (!skb)
380                                 goto error;
381                         usbnet_skb_return(dev, skb);
382                 }
383         }
384 err_ndp:
385         /* are there more NDPs to process? */
386         ndpoffset = le16_to_cpu(ndp16->wNextNdpIndex);
387         if (ndpoffset && loopcount--)
388                 goto next_ndp;
389 
390         return 1;
391 error:
392         return 0;
393 }
394 
395 static int cdc_mbim_suspend(struct usb_interface *intf, pm_message_t message)
396 {
397         int ret = -ENODEV;
398         struct usbnet *dev = usb_get_intfdata(intf);
399         struct cdc_mbim_state *info = (void *)&dev->data;
400         struct cdc_ncm_ctx *ctx = info->ctx;
401 
402         if (!ctx)
403                 goto error;
404 
405         /*
406          * Both usbnet_suspend() and subdriver->suspend() MUST return 0
407          * in system sleep context, otherwise, the resume callback has
408          * to recover device from previous suspend failure.
409          */
410         ret = usbnet_suspend(intf, message);
411         if (ret < 0)
412                 goto error;
413 
414         if (intf == ctx->control && info->subdriver && info->subdriver->suspend)
415                 ret = info->subdriver->suspend(intf, message);
416         if (ret < 0)
417                 usbnet_resume(intf);
418 
419 error:
420         return ret;
421 }
422 
423 static int cdc_mbim_resume(struct usb_interface *intf)
424 {
425         int  ret = 0;
426         struct usbnet *dev = usb_get_intfdata(intf);
427         struct cdc_mbim_state *info = (void *)&dev->data;
428         struct cdc_ncm_ctx *ctx = info->ctx;
429         bool callsub = (intf == ctx->control && info->subdriver && info->subdriver->resume);
430 
431         if (callsub)
432                 ret = info->subdriver->resume(intf);
433         if (ret < 0)
434                 goto err;
435         ret = usbnet_resume(intf);
436         if (ret < 0 && callsub)
437                 info->subdriver->suspend(intf, PMSG_SUSPEND);
438 err:
439         return ret;
440 }
441 
442 static const struct driver_info cdc_mbim_info = {
443         .description = "CDC MBIM",
444         .flags = FLAG_NO_SETINT | FLAG_MULTI_PACKET | FLAG_WWAN,
445         .bind = cdc_mbim_bind,
446         .unbind = cdc_mbim_unbind,
447         .manage_power = cdc_mbim_manage_power,
448         .rx_fixup = cdc_mbim_rx_fixup,
449         .tx_fixup = cdc_mbim_tx_fixup,
450 };
451 
452 /* MBIM and NCM devices should not need a ZLP after NTBs with
453  * dwNtbOutMaxSize length. Nevertheless, a number of devices from
454  * different vendor IDs will fail unless we send ZLPs, forcing us
455  * to make this the default.
456  *
457  * This default may cause a performance penalty for spec conforming
458  * devices wanting to take advantage of optimizations possible without
459  * ZLPs.  A whitelist is added in an attempt to avoid this for devices
460  * known to conform to the MBIM specification.
461  *
462  * All known devices supporting NCM compatibility mode are also
463  * conforming to the NCM and MBIM specifications. For this reason, the
464  * NCM subclass entry is also in the ZLP whitelist.
465  */
466 static const struct driver_info cdc_mbim_info_zlp = {
467         .description = "CDC MBIM",
468         .flags = FLAG_NO_SETINT | FLAG_MULTI_PACKET | FLAG_WWAN | FLAG_SEND_ZLP,
469         .bind = cdc_mbim_bind,
470         .unbind = cdc_mbim_unbind,
471         .manage_power = cdc_mbim_manage_power,
472         .rx_fixup = cdc_mbim_rx_fixup,
473         .tx_fixup = cdc_mbim_tx_fixup,
474 };
475 
476 static const struct usb_device_id mbim_devs[] = {
477         /* This duplicate NCM entry is intentional. MBIM devices can
478          * be disguised as NCM by default, and this is necessary to
479          * allow us to bind the correct driver_info to such devices.
480          *
481          * bind() will sort out this for us, selecting the correct
482          * entry and reject the other
483          */
484         { USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE),
485           .driver_info = (unsigned long)&cdc_mbim_info,
486         },
487         /* ZLP conformance whitelist: All Ericsson MBIM devices */
488         { USB_VENDOR_AND_INTERFACE_INFO(0x0bdb, USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
489           .driver_info = (unsigned long)&cdc_mbim_info,
490         },
491         /* default entry */
492         { USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_MBIM, USB_CDC_PROTO_NONE),
493           .driver_info = (unsigned long)&cdc_mbim_info_zlp,
494         },
495         {
496         },
497 };
498 MODULE_DEVICE_TABLE(usb, mbim_devs);
499 
500 static struct usb_driver cdc_mbim_driver = {
501         .name = "cdc_mbim",
502         .id_table = mbim_devs,
503         .probe = usbnet_probe,
504         .disconnect = usbnet_disconnect,
505         .suspend = cdc_mbim_suspend,
506         .resume = cdc_mbim_resume,
507         .reset_resume = cdc_mbim_resume,
508         .supports_autosuspend = 1,
509         .disable_hub_initiated_lpm = 1,
510 };
511 module_usb_driver(cdc_mbim_driver);
512 
513 MODULE_AUTHOR("Greg Suarez <gsuarez@smithmicro.com>");
514 MODULE_AUTHOR("Bjørn Mork <bjorn@mork.no>");
515 MODULE_DESCRIPTION("USB CDC MBIM host driver");
516 MODULE_LICENSE("GPL");
517 

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