1 /*
2 * CAIF Interface registration.
3 * Copyright (C) ST-Ericsson AB 2010
4 * Author: Sjur Brendeland
5 * License terms: GNU General Public License (GPL) version 2
6 *
7 * Borrowed heavily from file: pn_dev.c. Thanks to Remi Denis-Courmont
8 * and Sakari Ailus <sakari.ailus@nokia.com>
9 */
10
11 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
12
13 #include <linux/kernel.h>
14 #include <linux/if_arp.h>
15 #include <linux/net.h>
16 #include <linux/netdevice.h>
17 #include <linux/mutex.h>
18 #include <linux/module.h>
19 #include <linux/spinlock.h>
20 #include <net/netns/generic.h>
21 #include <net/net_namespace.h>
22 #include <net/pkt_sched.h>
23 #include <net/caif/caif_device.h>
24 #include <net/caif/caif_layer.h>
25 #include <net/caif/caif_dev.h>
26 #include <net/caif/cfpkt.h>
27 #include <net/caif/cfcnfg.h>
28 #include <net/caif/cfserl.h>
29
30 MODULE_LICENSE("GPL");
31
32 /* Used for local tracking of the CAIF net devices */
33 struct caif_device_entry {
34 struct cflayer layer;
35 struct list_head list;
36 struct net_device *netdev;
37 int __percpu *pcpu_refcnt;
38 spinlock_t flow_lock;
39 struct sk_buff *xoff_skb;
40 void (*xoff_skb_dtor)(struct sk_buff *skb);
41 bool xoff;
42 };
43
44 struct caif_device_entry_list {
45 struct list_head list;
46 /* Protects simulanous deletes in list */
47 struct mutex lock;
48 };
49
50 struct caif_net {
51 struct cfcnfg *cfg;
52 struct caif_device_entry_list caifdevs;
53 };
54
55 static unsigned int caif_net_id;
56 static int q_high = 50; /* Percent */
57
get_cfcnfg(struct net * net)58 struct cfcnfg *get_cfcnfg(struct net *net)
59 {
60 struct caif_net *caifn;
61 caifn = net_generic(net, caif_net_id);
62 return caifn->cfg;
63 }
64 EXPORT_SYMBOL(get_cfcnfg);
65
caif_device_list(struct net * net)66 static struct caif_device_entry_list *caif_device_list(struct net *net)
67 {
68 struct caif_net *caifn;
69 caifn = net_generic(net, caif_net_id);
70 return &caifn->caifdevs;
71 }
72
caifd_put(struct caif_device_entry * e)73 static void caifd_put(struct caif_device_entry *e)
74 {
75 this_cpu_dec(*e->pcpu_refcnt);
76 }
77
caifd_hold(struct caif_device_entry * e)78 static void caifd_hold(struct caif_device_entry *e)
79 {
80 this_cpu_inc(*e->pcpu_refcnt);
81 }
82
caifd_refcnt_read(struct caif_device_entry * e)83 static int caifd_refcnt_read(struct caif_device_entry *e)
84 {
85 int i, refcnt = 0;
86 for_each_possible_cpu(i)
87 refcnt += *per_cpu_ptr(e->pcpu_refcnt, i);
88 return refcnt;
89 }
90
91 /* Allocate new CAIF device. */
caif_device_alloc(struct net_device * dev)92 static struct caif_device_entry *caif_device_alloc(struct net_device *dev)
93 {
94 struct caif_device_entry *caifd;
95
96 caifd = kzalloc(sizeof(*caifd), GFP_KERNEL);
97 if (!caifd)
98 return NULL;
99 caifd->pcpu_refcnt = alloc_percpu(int);
100 if (!caifd->pcpu_refcnt) {
101 kfree(caifd);
102 return NULL;
103 }
104 caifd->netdev = dev;
105 dev_hold(dev);
106 return caifd;
107 }
108
caif_get(struct net_device * dev)109 static struct caif_device_entry *caif_get(struct net_device *dev)
110 {
111 struct caif_device_entry_list *caifdevs =
112 caif_device_list(dev_net(dev));
113 struct caif_device_entry *caifd;
114
115 list_for_each_entry_rcu(caifd, &caifdevs->list, list) {
116 if (caifd->netdev == dev)
117 return caifd;
118 }
119 return NULL;
120 }
121
caif_flow_cb(struct sk_buff * skb)122 static void caif_flow_cb(struct sk_buff *skb)
123 {
124 struct caif_device_entry *caifd;
125 void (*dtor)(struct sk_buff *skb) = NULL;
126 bool send_xoff;
127
128 WARN_ON(skb->dev == NULL);
129
130 rcu_read_lock();
131 caifd = caif_get(skb->dev);
132
133 WARN_ON(caifd == NULL);
134 if (!caifd) {
135 rcu_read_unlock();
136 return;
137 }
138
139 caifd_hold(caifd);
140 rcu_read_unlock();
141
142 spin_lock_bh(&caifd->flow_lock);
143 send_xoff = caifd->xoff;
144 caifd->xoff = 0;
145 dtor = caifd->xoff_skb_dtor;
146
147 if (WARN_ON(caifd->xoff_skb != skb))
148 skb = NULL;
149
150 caifd->xoff_skb = NULL;
151 caifd->xoff_skb_dtor = NULL;
152
153 spin_unlock_bh(&caifd->flow_lock);
154
155 if (dtor && skb)
156 dtor(skb);
157
158 if (send_xoff)
159 caifd->layer.up->
160 ctrlcmd(caifd->layer.up,
161 _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND,
162 caifd->layer.id);
163 caifd_put(caifd);
164 }
165
transmit(struct cflayer * layer,struct cfpkt * pkt)166 static int transmit(struct cflayer *layer, struct cfpkt *pkt)
167 {
168 int err, high = 0, qlen = 0;
169 struct caif_device_entry *caifd =
170 container_of(layer, struct caif_device_entry, layer);
171 struct sk_buff *skb;
172 struct netdev_queue *txq;
173
174 rcu_read_lock_bh();
175
176 skb = cfpkt_tonative(pkt);
177 skb->dev = caifd->netdev;
178 skb_reset_network_header(skb);
179 skb->protocol = htons(ETH_P_CAIF);
180
181 /* Check if we need to handle xoff */
182 if (likely(caifd->netdev->priv_flags & IFF_NO_QUEUE))
183 goto noxoff;
184
185 if (unlikely(caifd->xoff))
186 goto noxoff;
187
188 if (likely(!netif_queue_stopped(caifd->netdev))) {
189 /* If we run with a TX queue, check if the queue is too long*/
190 txq = netdev_get_tx_queue(skb->dev, 0);
191 qlen = qdisc_qlen(rcu_dereference_bh(txq->qdisc));
192
193 if (likely(qlen == 0))
194 goto noxoff;
195
196 high = (caifd->netdev->tx_queue_len * q_high) / 100;
197 if (likely(qlen < high))
198 goto noxoff;
199 }
200
201 /* Hold lock while accessing xoff */
202 spin_lock_bh(&caifd->flow_lock);
203 if (caifd->xoff) {
204 spin_unlock_bh(&caifd->flow_lock);
205 goto noxoff;
206 }
207
208 /*
209 * Handle flow off, we do this by temporary hi-jacking this
210 * skb's destructor function, and replace it with our own
211 * flow-on callback. The callback will set flow-on and call
212 * the original destructor.
213 */
214
215 pr_debug("queue has stopped(%d) or is full (%d > %d)\n",
216 netif_queue_stopped(caifd->netdev),
217 qlen, high);
218 caifd->xoff = 1;
219 caifd->xoff_skb = skb;
220 caifd->xoff_skb_dtor = skb->destructor;
221 skb->destructor = caif_flow_cb;
222 spin_unlock_bh(&caifd->flow_lock);
223
224 caifd->layer.up->ctrlcmd(caifd->layer.up,
225 _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
226 caifd->layer.id);
227 noxoff:
228 rcu_read_unlock_bh();
229
230 err = dev_queue_xmit(skb);
231 if (err > 0)
232 err = -EIO;
233
234 return err;
235 }
236
237 /*
238 * Stuff received packets into the CAIF stack.
239 * On error, returns non-zero and releases the skb.
240 */
receive(struct sk_buff * skb,struct net_device * dev,struct packet_type * pkttype,struct net_device * orig_dev)241 static int receive(struct sk_buff *skb, struct net_device *dev,
242 struct packet_type *pkttype, struct net_device *orig_dev)
243 {
244 struct cfpkt *pkt;
245 struct caif_device_entry *caifd;
246 int err;
247
248 pkt = cfpkt_fromnative(CAIF_DIR_IN, skb);
249
250 rcu_read_lock();
251 caifd = caif_get(dev);
252
253 if (!caifd || !caifd->layer.up || !caifd->layer.up->receive ||
254 !netif_oper_up(caifd->netdev)) {
255 rcu_read_unlock();
256 kfree_skb(skb);
257 return NET_RX_DROP;
258 }
259
260 /* Hold reference to netdevice while using CAIF stack */
261 caifd_hold(caifd);
262 rcu_read_unlock();
263
264 err = caifd->layer.up->receive(caifd->layer.up, pkt);
265
266 /* For -EILSEQ the packet is not freed so so it now */
267 if (err == -EILSEQ)
268 cfpkt_destroy(pkt);
269
270 /* Release reference to stack upwards */
271 caifd_put(caifd);
272
273 if (err != 0)
274 err = NET_RX_DROP;
275 return err;
276 }
277
278 static struct packet_type caif_packet_type __read_mostly = {
279 .type = cpu_to_be16(ETH_P_CAIF),
280 .func = receive,
281 };
282
dev_flowctrl(struct net_device * dev,int on)283 static void dev_flowctrl(struct net_device *dev, int on)
284 {
285 struct caif_device_entry *caifd;
286
287 rcu_read_lock();
288
289 caifd = caif_get(dev);
290 if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
291 rcu_read_unlock();
292 return;
293 }
294
295 caifd_hold(caifd);
296 rcu_read_unlock();
297
298 caifd->layer.up->ctrlcmd(caifd->layer.up,
299 on ?
300 _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND :
301 _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
302 caifd->layer.id);
303 caifd_put(caifd);
304 }
305
caif_enroll_dev(struct net_device * dev,struct caif_dev_common * caifdev,struct cflayer * link_support,int head_room,struct cflayer ** layer,int (** rcv_func)(struct sk_buff *,struct net_device *,struct packet_type *,struct net_device *))306 void caif_enroll_dev(struct net_device *dev, struct caif_dev_common *caifdev,
307 struct cflayer *link_support, int head_room,
308 struct cflayer **layer,
309 int (**rcv_func)(struct sk_buff *, struct net_device *,
310 struct packet_type *,
311 struct net_device *))
312 {
313 struct caif_device_entry *caifd;
314 enum cfcnfg_phy_preference pref;
315 struct cfcnfg *cfg = get_cfcnfg(dev_net(dev));
316 struct caif_device_entry_list *caifdevs;
317
318 caifdevs = caif_device_list(dev_net(dev));
319 caifd = caif_device_alloc(dev);
320 if (!caifd)
321 return;
322 *layer = &caifd->layer;
323 spin_lock_init(&caifd->flow_lock);
324
325 switch (caifdev->link_select) {
326 case CAIF_LINK_HIGH_BANDW:
327 pref = CFPHYPREF_HIGH_BW;
328 break;
329 case CAIF_LINK_LOW_LATENCY:
330 pref = CFPHYPREF_LOW_LAT;
331 break;
332 default:
333 pref = CFPHYPREF_HIGH_BW;
334 break;
335 }
336 mutex_lock(&caifdevs->lock);
337 list_add_rcu(&caifd->list, &caifdevs->list);
338
339 strlcpy(caifd->layer.name, dev->name,
340 sizeof(caifd->layer.name));
341 caifd->layer.transmit = transmit;
342 cfcnfg_add_phy_layer(cfg,
343 dev,
344 &caifd->layer,
345 pref,
346 link_support,
347 caifdev->use_fcs,
348 head_room);
349 mutex_unlock(&caifdevs->lock);
350 if (rcv_func)
351 *rcv_func = receive;
352 }
353 EXPORT_SYMBOL(caif_enroll_dev);
354
355 /* notify Caif of device events */
caif_device_notify(struct notifier_block * me,unsigned long what,void * ptr)356 static int caif_device_notify(struct notifier_block *me, unsigned long what,
357 void *ptr)
358 {
359 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
360 struct caif_device_entry *caifd = NULL;
361 struct caif_dev_common *caifdev;
362 struct cfcnfg *cfg;
363 struct cflayer *layer, *link_support;
364 int head_room = 0;
365 struct caif_device_entry_list *caifdevs;
366
367 cfg = get_cfcnfg(dev_net(dev));
368 caifdevs = caif_device_list(dev_net(dev));
369
370 caifd = caif_get(dev);
371 if (caifd == NULL && dev->type != ARPHRD_CAIF)
372 return 0;
373
374 switch (what) {
375 case NETDEV_REGISTER:
376 if (caifd != NULL)
377 break;
378
379 caifdev = netdev_priv(dev);
380
381 link_support = NULL;
382 if (caifdev->use_frag) {
383 head_room = 1;
384 link_support = cfserl_create(dev->ifindex,
385 caifdev->use_stx);
386 if (!link_support) {
387 pr_warn("Out of memory\n");
388 break;
389 }
390 }
391 caif_enroll_dev(dev, caifdev, link_support, head_room,
392 &layer, NULL);
393 caifdev->flowctrl = dev_flowctrl;
394 break;
395
396 case NETDEV_UP:
397 rcu_read_lock();
398
399 caifd = caif_get(dev);
400 if (caifd == NULL) {
401 rcu_read_unlock();
402 break;
403 }
404
405 caifd->xoff = 0;
406 cfcnfg_set_phy_state(cfg, &caifd->layer, true);
407 rcu_read_unlock();
408
409 break;
410
411 case NETDEV_DOWN:
412 rcu_read_lock();
413
414 caifd = caif_get(dev);
415 if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
416 rcu_read_unlock();
417 return -EINVAL;
418 }
419
420 cfcnfg_set_phy_state(cfg, &caifd->layer, false);
421 caifd_hold(caifd);
422 rcu_read_unlock();
423
424 caifd->layer.up->ctrlcmd(caifd->layer.up,
425 _CAIF_CTRLCMD_PHYIF_DOWN_IND,
426 caifd->layer.id);
427
428 spin_lock_bh(&caifd->flow_lock);
429
430 /*
431 * Replace our xoff-destructor with original destructor.
432 * We trust that skb->destructor *always* is called before
433 * the skb reference is invalid. The hijacked SKB destructor
434 * takes the flow_lock so manipulating the skb->destructor here
435 * should be safe.
436 */
437 if (caifd->xoff_skb_dtor != NULL && caifd->xoff_skb != NULL)
438 caifd->xoff_skb->destructor = caifd->xoff_skb_dtor;
439
440 caifd->xoff = 0;
441 caifd->xoff_skb_dtor = NULL;
442 caifd->xoff_skb = NULL;
443
444 spin_unlock_bh(&caifd->flow_lock);
445 caifd_put(caifd);
446 break;
447
448 case NETDEV_UNREGISTER:
449 mutex_lock(&caifdevs->lock);
450
451 caifd = caif_get(dev);
452 if (caifd == NULL) {
453 mutex_unlock(&caifdevs->lock);
454 break;
455 }
456 list_del_rcu(&caifd->list);
457
458 /*
459 * NETDEV_UNREGISTER is called repeatedly until all reference
460 * counts for the net-device are released. If references to
461 * caifd is taken, simply ignore NETDEV_UNREGISTER and wait for
462 * the next call to NETDEV_UNREGISTER.
463 *
464 * If any packets are in flight down the CAIF Stack,
465 * cfcnfg_del_phy_layer will return nonzero.
466 * If no packets are in flight, the CAIF Stack associated
467 * with the net-device un-registering is freed.
468 */
469
470 if (caifd_refcnt_read(caifd) != 0 ||
471 cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0) {
472
473 pr_info("Wait for device inuse\n");
474 /* Enrole device if CAIF Stack is still in use */
475 list_add_rcu(&caifd->list, &caifdevs->list);
476 mutex_unlock(&caifdevs->lock);
477 break;
478 }
479
480 synchronize_rcu();
481 dev_put(caifd->netdev);
482 free_percpu(caifd->pcpu_refcnt);
483 kfree(caifd);
484
485 mutex_unlock(&caifdevs->lock);
486 break;
487 }
488 return 0;
489 }
490
491 static struct notifier_block caif_device_notifier = {
492 .notifier_call = caif_device_notify,
493 .priority = 0,
494 };
495
496 /* Per-namespace Caif devices handling */
caif_init_net(struct net * net)497 static int caif_init_net(struct net *net)
498 {
499 struct caif_net *caifn = net_generic(net, caif_net_id);
500 INIT_LIST_HEAD(&caifn->caifdevs.list);
501 mutex_init(&caifn->caifdevs.lock);
502
503 caifn->cfg = cfcnfg_create();
504 if (!caifn->cfg)
505 return -ENOMEM;
506
507 return 0;
508 }
509
caif_exit_net(struct net * net)510 static void caif_exit_net(struct net *net)
511 {
512 struct caif_device_entry *caifd, *tmp;
513 struct caif_device_entry_list *caifdevs =
514 caif_device_list(net);
515 struct cfcnfg *cfg = get_cfcnfg(net);
516
517 rtnl_lock();
518 mutex_lock(&caifdevs->lock);
519
520 list_for_each_entry_safe(caifd, tmp, &caifdevs->list, list) {
521 int i = 0;
522 list_del_rcu(&caifd->list);
523 cfcnfg_set_phy_state(cfg, &caifd->layer, false);
524
525 while (i < 10 &&
526 (caifd_refcnt_read(caifd) != 0 ||
527 cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0)) {
528
529 pr_info("Wait for device inuse\n");
530 msleep(250);
531 i++;
532 }
533 synchronize_rcu();
534 dev_put(caifd->netdev);
535 free_percpu(caifd->pcpu_refcnt);
536 kfree(caifd);
537 }
538 cfcnfg_remove(cfg);
539
540 mutex_unlock(&caifdevs->lock);
541 rtnl_unlock();
542 }
543
544 static struct pernet_operations caif_net_ops = {
545 .init = caif_init_net,
546 .exit = caif_exit_net,
547 .id = &caif_net_id,
548 .size = sizeof(struct caif_net),
549 };
550
551 /* Initialize Caif devices list */
caif_device_init(void)552 static int __init caif_device_init(void)
553 {
554 int result;
555
556 result = register_pernet_subsys(&caif_net_ops);
557
558 if (result)
559 return result;
560
561 register_netdevice_notifier(&caif_device_notifier);
562 dev_add_pack(&caif_packet_type);
563
564 return result;
565 }
566
caif_device_exit(void)567 static void __exit caif_device_exit(void)
568 {
569 unregister_netdevice_notifier(&caif_device_notifier);
570 dev_remove_pack(&caif_packet_type);
571 unregister_pernet_subsys(&caif_net_ops);
572 }
573
574 module_init(caif_device_init);
575 module_exit(caif_device_exit);
576
