1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * CAIF Interface registration. |
4 | * Copyright (C) ST-Ericsson AB 2010 |
5 | * Author: Sjur Brendeland |
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 | |
58 | struct cfcnfg *get_cfcnfg(struct net *net) |
59 | { |
60 | struct caif_net *caifn; |
61 | caifn = net_generic(net, id: caif_net_id); |
62 | return caifn->cfg; |
63 | } |
64 | EXPORT_SYMBOL(get_cfcnfg); |
65 | |
66 | static struct caif_device_entry_list *caif_device_list(struct net *net) |
67 | { |
68 | struct caif_net *caifn; |
69 | caifn = net_generic(net, id: caif_net_id); |
70 | return &caifn->caifdevs; |
71 | } |
72 | |
73 | static void caifd_put(struct caif_device_entry *e) |
74 | { |
75 | this_cpu_dec(*e->pcpu_refcnt); |
76 | } |
77 | |
78 | static void caifd_hold(struct caif_device_entry *e) |
79 | { |
80 | this_cpu_inc(*e->pcpu_refcnt); |
81 | } |
82 | |
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. */ |
92 | static struct caif_device_entry *caif_device_alloc(struct net_device *dev) |
93 | { |
94 | struct caif_device_entry *caifd; |
95 | |
96 | caifd = kzalloc(size: sizeof(*caifd), GFP_KERNEL); |
97 | if (!caifd) |
98 | return NULL; |
99 | caifd->pcpu_refcnt = alloc_percpu(int); |
100 | if (!caifd->pcpu_refcnt) { |
101 | kfree(objp: caifd); |
102 | return NULL; |
103 | } |
104 | caifd->netdev = dev; |
105 | dev_hold(dev); |
106 | return caifd; |
107 | } |
108 | |
109 | static struct caif_device_entry *caif_get(struct net_device *dev) |
110 | { |
111 | struct caif_device_entry_list *caifdevs = |
112 | caif_device_list(net: dev_net(dev)); |
113 | struct caif_device_entry *caifd; |
114 | |
115 | list_for_each_entry_rcu(caifd, &caifdevs->list, list, |
116 | lockdep_rtnl_is_held()) { |
117 | if (caifd->netdev == dev) |
118 | return caifd; |
119 | } |
120 | return NULL; |
121 | } |
122 | |
123 | static void caif_flow_cb(struct sk_buff *skb) |
124 | { |
125 | struct caif_device_entry *caifd; |
126 | void (*dtor)(struct sk_buff *skb) = NULL; |
127 | bool send_xoff; |
128 | |
129 | WARN_ON(skb->dev == NULL); |
130 | |
131 | rcu_read_lock(); |
132 | caifd = caif_get(dev: skb->dev); |
133 | |
134 | WARN_ON(caifd == NULL); |
135 | if (!caifd) { |
136 | rcu_read_unlock(); |
137 | return; |
138 | } |
139 | |
140 | caifd_hold(e: caifd); |
141 | rcu_read_unlock(); |
142 | |
143 | spin_lock_bh(lock: &caifd->flow_lock); |
144 | send_xoff = caifd->xoff; |
145 | caifd->xoff = false; |
146 | dtor = caifd->xoff_skb_dtor; |
147 | |
148 | if (WARN_ON(caifd->xoff_skb != skb)) |
149 | skb = NULL; |
150 | |
151 | caifd->xoff_skb = NULL; |
152 | caifd->xoff_skb_dtor = NULL; |
153 | |
154 | spin_unlock_bh(lock: &caifd->flow_lock); |
155 | |
156 | if (dtor && skb) |
157 | dtor(skb); |
158 | |
159 | if (send_xoff) |
160 | caifd->layer.up-> |
161 | ctrlcmd(caifd->layer.up, |
162 | _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND, |
163 | caifd->layer.id); |
164 | caifd_put(e: caifd); |
165 | } |
166 | |
167 | static int transmit(struct cflayer *layer, struct cfpkt *pkt) |
168 | { |
169 | int err, high = 0, qlen = 0; |
170 | struct caif_device_entry *caifd = |
171 | container_of(layer, struct caif_device_entry, layer); |
172 | struct sk_buff *skb; |
173 | struct netdev_queue *txq; |
174 | |
175 | rcu_read_lock_bh(); |
176 | |
177 | skb = cfpkt_tonative(pkt); |
178 | skb->dev = caifd->netdev; |
179 | skb_reset_network_header(skb); |
180 | skb->protocol = htons(ETH_P_CAIF); |
181 | |
182 | /* Check if we need to handle xoff */ |
183 | if (likely(caifd->netdev->priv_flags & IFF_NO_QUEUE)) |
184 | goto noxoff; |
185 | |
186 | if (unlikely(caifd->xoff)) |
187 | goto noxoff; |
188 | |
189 | if (likely(!netif_queue_stopped(caifd->netdev))) { |
190 | struct Qdisc *sch; |
191 | |
192 | /* If we run with a TX queue, check if the queue is too long*/ |
193 | txq = netdev_get_tx_queue(dev: skb->dev, index: 0); |
194 | sch = rcu_dereference_bh(txq->qdisc); |
195 | if (likely(qdisc_is_empty(sch))) |
196 | goto noxoff; |
197 | |
198 | /* can check for explicit qdisc len value only !NOLOCK, |
199 | * always set flow off otherwise |
200 | */ |
201 | high = (caifd->netdev->tx_queue_len * q_high) / 100; |
202 | if (!(sch->flags & TCQ_F_NOLOCK) && likely(sch->q.qlen < high)) |
203 | goto noxoff; |
204 | } |
205 | |
206 | /* Hold lock while accessing xoff */ |
207 | spin_lock_bh(lock: &caifd->flow_lock); |
208 | if (caifd->xoff) { |
209 | spin_unlock_bh(lock: &caifd->flow_lock); |
210 | goto noxoff; |
211 | } |
212 | |
213 | /* |
214 | * Handle flow off, we do this by temporary hi-jacking this |
215 | * skb's destructor function, and replace it with our own |
216 | * flow-on callback. The callback will set flow-on and call |
217 | * the original destructor. |
218 | */ |
219 | |
220 | pr_debug("queue has stopped(%d) or is full (%d > %d)\n" , |
221 | netif_queue_stopped(caifd->netdev), |
222 | qlen, high); |
223 | caifd->xoff = true; |
224 | caifd->xoff_skb = skb; |
225 | caifd->xoff_skb_dtor = skb->destructor; |
226 | skb->destructor = caif_flow_cb; |
227 | spin_unlock_bh(lock: &caifd->flow_lock); |
228 | |
229 | caifd->layer.up->ctrlcmd(caifd->layer.up, |
230 | _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND, |
231 | caifd->layer.id); |
232 | noxoff: |
233 | rcu_read_unlock_bh(); |
234 | |
235 | err = dev_queue_xmit(skb); |
236 | if (err > 0) |
237 | err = -EIO; |
238 | |
239 | return err; |
240 | } |
241 | |
242 | /* |
243 | * Stuff received packets into the CAIF stack. |
244 | * On error, returns non-zero and releases the skb. |
245 | */ |
246 | static int receive(struct sk_buff *skb, struct net_device *dev, |
247 | struct packet_type *pkttype, struct net_device *orig_dev) |
248 | { |
249 | struct cfpkt *pkt; |
250 | struct caif_device_entry *caifd; |
251 | int err; |
252 | |
253 | pkt = cfpkt_fromnative(dir: CAIF_DIR_IN, nativepkt: skb); |
254 | |
255 | rcu_read_lock(); |
256 | caifd = caif_get(dev); |
257 | |
258 | if (!caifd || !caifd->layer.up || !caifd->layer.up->receive || |
259 | !netif_oper_up(dev: caifd->netdev)) { |
260 | rcu_read_unlock(); |
261 | kfree_skb(skb); |
262 | return NET_RX_DROP; |
263 | } |
264 | |
265 | /* Hold reference to netdevice while using CAIF stack */ |
266 | caifd_hold(e: caifd); |
267 | rcu_read_unlock(); |
268 | |
269 | err = caifd->layer.up->receive(caifd->layer.up, pkt); |
270 | |
271 | /* For -EILSEQ the packet is not freed so free it now */ |
272 | if (err == -EILSEQ) |
273 | cfpkt_destroy(pkt); |
274 | |
275 | /* Release reference to stack upwards */ |
276 | caifd_put(e: caifd); |
277 | |
278 | if (err != 0) |
279 | err = NET_RX_DROP; |
280 | return err; |
281 | } |
282 | |
283 | static struct packet_type caif_packet_type __read_mostly = { |
284 | .type = cpu_to_be16(ETH_P_CAIF), |
285 | .func = receive, |
286 | }; |
287 | |
288 | static void dev_flowctrl(struct net_device *dev, int on) |
289 | { |
290 | struct caif_device_entry *caifd; |
291 | |
292 | rcu_read_lock(); |
293 | |
294 | caifd = caif_get(dev); |
295 | if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) { |
296 | rcu_read_unlock(); |
297 | return; |
298 | } |
299 | |
300 | caifd_hold(e: caifd); |
301 | rcu_read_unlock(); |
302 | |
303 | caifd->layer.up->ctrlcmd(caifd->layer.up, |
304 | on ? |
305 | _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND : |
306 | _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND, |
307 | caifd->layer.id); |
308 | caifd_put(e: caifd); |
309 | } |
310 | |
311 | int caif_enroll_dev(struct net_device *dev, struct caif_dev_common *caifdev, |
312 | struct cflayer *link_support, int head_room, |
313 | struct cflayer **layer, |
314 | int (**rcv_func)(struct sk_buff *, struct net_device *, |
315 | struct packet_type *, |
316 | struct net_device *)) |
317 | { |
318 | struct caif_device_entry *caifd; |
319 | enum cfcnfg_phy_preference pref; |
320 | struct cfcnfg *cfg = get_cfcnfg(dev_net(dev)); |
321 | struct caif_device_entry_list *caifdevs; |
322 | int res; |
323 | |
324 | caifdevs = caif_device_list(net: dev_net(dev)); |
325 | caifd = caif_device_alloc(dev); |
326 | if (!caifd) |
327 | return -ENOMEM; |
328 | *layer = &caifd->layer; |
329 | spin_lock_init(&caifd->flow_lock); |
330 | |
331 | switch (caifdev->link_select) { |
332 | case CAIF_LINK_HIGH_BANDW: |
333 | pref = CFPHYPREF_HIGH_BW; |
334 | break; |
335 | case CAIF_LINK_LOW_LATENCY: |
336 | pref = CFPHYPREF_LOW_LAT; |
337 | break; |
338 | default: |
339 | pref = CFPHYPREF_HIGH_BW; |
340 | break; |
341 | } |
342 | mutex_lock(&caifdevs->lock); |
343 | list_add_rcu(new: &caifd->list, head: &caifdevs->list); |
344 | |
345 | strscpy(p: caifd->layer.name, q: dev->name, |
346 | size: sizeof(caifd->layer.name)); |
347 | caifd->layer.transmit = transmit; |
348 | res = cfcnfg_add_phy_layer(cnfg: cfg, |
349 | dev, |
350 | phy_layer: &caifd->layer, |
351 | pref, |
352 | link_support, |
353 | fcs: caifdev->use_fcs, |
354 | head_room); |
355 | mutex_unlock(lock: &caifdevs->lock); |
356 | if (rcv_func) |
357 | *rcv_func = receive; |
358 | return res; |
359 | } |
360 | EXPORT_SYMBOL(caif_enroll_dev); |
361 | |
362 | /* notify Caif of device events */ |
363 | static int caif_device_notify(struct notifier_block *me, unsigned long what, |
364 | void *ptr) |
365 | { |
366 | struct net_device *dev = netdev_notifier_info_to_dev(info: ptr); |
367 | struct caif_device_entry *caifd = NULL; |
368 | struct caif_dev_common *caifdev; |
369 | struct cfcnfg *cfg; |
370 | struct cflayer *layer, *link_support; |
371 | int head_room = 0; |
372 | struct caif_device_entry_list *caifdevs; |
373 | int res; |
374 | |
375 | cfg = get_cfcnfg(dev_net(dev)); |
376 | caifdevs = caif_device_list(net: dev_net(dev)); |
377 | |
378 | caifd = caif_get(dev); |
379 | if (caifd == NULL && dev->type != ARPHRD_CAIF) |
380 | return 0; |
381 | |
382 | switch (what) { |
383 | case NETDEV_REGISTER: |
384 | if (caifd != NULL) |
385 | break; |
386 | |
387 | caifdev = netdev_priv(dev); |
388 | |
389 | link_support = NULL; |
390 | if (caifdev->use_frag) { |
391 | head_room = 1; |
392 | link_support = cfserl_create(instance: dev->ifindex, |
393 | use_stx: caifdev->use_stx); |
394 | if (!link_support) { |
395 | pr_warn("Out of memory\n" ); |
396 | break; |
397 | } |
398 | } |
399 | res = caif_enroll_dev(dev, caifdev, link_support, head_room, |
400 | &layer, NULL); |
401 | if (res) |
402 | cfserl_release(layer: link_support); |
403 | caifdev->flowctrl = dev_flowctrl; |
404 | break; |
405 | |
406 | case NETDEV_UP: |
407 | rcu_read_lock(); |
408 | |
409 | caifd = caif_get(dev); |
410 | if (caifd == NULL) { |
411 | rcu_read_unlock(); |
412 | break; |
413 | } |
414 | |
415 | caifd->xoff = false; |
416 | cfcnfg_set_phy_state(cnfg: cfg, phy_layer: &caifd->layer, up: true); |
417 | rcu_read_unlock(); |
418 | |
419 | break; |
420 | |
421 | case NETDEV_DOWN: |
422 | rcu_read_lock(); |
423 | |
424 | caifd = caif_get(dev); |
425 | if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) { |
426 | rcu_read_unlock(); |
427 | return -EINVAL; |
428 | } |
429 | |
430 | cfcnfg_set_phy_state(cnfg: cfg, phy_layer: &caifd->layer, up: false); |
431 | caifd_hold(e: caifd); |
432 | rcu_read_unlock(); |
433 | |
434 | caifd->layer.up->ctrlcmd(caifd->layer.up, |
435 | _CAIF_CTRLCMD_PHYIF_DOWN_IND, |
436 | caifd->layer.id); |
437 | |
438 | spin_lock_bh(lock: &caifd->flow_lock); |
439 | |
440 | /* |
441 | * Replace our xoff-destructor with original destructor. |
442 | * We trust that skb->destructor *always* is called before |
443 | * the skb reference is invalid. The hijacked SKB destructor |
444 | * takes the flow_lock so manipulating the skb->destructor here |
445 | * should be safe. |
446 | */ |
447 | if (caifd->xoff_skb_dtor != NULL && caifd->xoff_skb != NULL) |
448 | caifd->xoff_skb->destructor = caifd->xoff_skb_dtor; |
449 | |
450 | caifd->xoff = false; |
451 | caifd->xoff_skb_dtor = NULL; |
452 | caifd->xoff_skb = NULL; |
453 | |
454 | spin_unlock_bh(lock: &caifd->flow_lock); |
455 | caifd_put(e: caifd); |
456 | break; |
457 | |
458 | case NETDEV_UNREGISTER: |
459 | mutex_lock(&caifdevs->lock); |
460 | |
461 | caifd = caif_get(dev); |
462 | if (caifd == NULL) { |
463 | mutex_unlock(lock: &caifdevs->lock); |
464 | break; |
465 | } |
466 | list_del_rcu(entry: &caifd->list); |
467 | |
468 | /* |
469 | * NETDEV_UNREGISTER is called repeatedly until all reference |
470 | * counts for the net-device are released. If references to |
471 | * caifd is taken, simply ignore NETDEV_UNREGISTER and wait for |
472 | * the next call to NETDEV_UNREGISTER. |
473 | * |
474 | * If any packets are in flight down the CAIF Stack, |
475 | * cfcnfg_del_phy_layer will return nonzero. |
476 | * If no packets are in flight, the CAIF Stack associated |
477 | * with the net-device un-registering is freed. |
478 | */ |
479 | |
480 | if (caifd_refcnt_read(e: caifd) != 0 || |
481 | cfcnfg_del_phy_layer(cnfg: cfg, phy_layer: &caifd->layer) != 0) { |
482 | |
483 | pr_info("Wait for device inuse\n" ); |
484 | /* Enrole device if CAIF Stack is still in use */ |
485 | list_add_rcu(new: &caifd->list, head: &caifdevs->list); |
486 | mutex_unlock(lock: &caifdevs->lock); |
487 | break; |
488 | } |
489 | |
490 | synchronize_rcu(); |
491 | dev_put(dev: caifd->netdev); |
492 | free_percpu(pdata: caifd->pcpu_refcnt); |
493 | kfree(objp: caifd); |
494 | |
495 | mutex_unlock(lock: &caifdevs->lock); |
496 | break; |
497 | } |
498 | return 0; |
499 | } |
500 | |
501 | static struct notifier_block caif_device_notifier = { |
502 | .notifier_call = caif_device_notify, |
503 | .priority = 0, |
504 | }; |
505 | |
506 | /* Per-namespace Caif devices handling */ |
507 | static int caif_init_net(struct net *net) |
508 | { |
509 | struct caif_net *caifn = net_generic(net, id: caif_net_id); |
510 | INIT_LIST_HEAD(list: &caifn->caifdevs.list); |
511 | mutex_init(&caifn->caifdevs.lock); |
512 | |
513 | caifn->cfg = cfcnfg_create(); |
514 | if (!caifn->cfg) |
515 | return -ENOMEM; |
516 | |
517 | return 0; |
518 | } |
519 | |
520 | static void caif_exit_net(struct net *net) |
521 | { |
522 | struct caif_device_entry *caifd, *tmp; |
523 | struct caif_device_entry_list *caifdevs = |
524 | caif_device_list(net); |
525 | struct cfcnfg *cfg = get_cfcnfg(net); |
526 | |
527 | rtnl_lock(); |
528 | mutex_lock(&caifdevs->lock); |
529 | |
530 | list_for_each_entry_safe(caifd, tmp, &caifdevs->list, list) { |
531 | int i = 0; |
532 | list_del_rcu(entry: &caifd->list); |
533 | cfcnfg_set_phy_state(cnfg: cfg, phy_layer: &caifd->layer, up: false); |
534 | |
535 | while (i < 10 && |
536 | (caifd_refcnt_read(e: caifd) != 0 || |
537 | cfcnfg_del_phy_layer(cnfg: cfg, phy_layer: &caifd->layer) != 0)) { |
538 | |
539 | pr_info("Wait for device inuse\n" ); |
540 | msleep(msecs: 250); |
541 | i++; |
542 | } |
543 | synchronize_rcu(); |
544 | dev_put(dev: caifd->netdev); |
545 | free_percpu(pdata: caifd->pcpu_refcnt); |
546 | kfree(objp: caifd); |
547 | } |
548 | cfcnfg_remove(cfg); |
549 | |
550 | mutex_unlock(lock: &caifdevs->lock); |
551 | rtnl_unlock(); |
552 | } |
553 | |
554 | static struct pernet_operations caif_net_ops = { |
555 | .init = caif_init_net, |
556 | .exit = caif_exit_net, |
557 | .id = &caif_net_id, |
558 | .size = sizeof(struct caif_net), |
559 | }; |
560 | |
561 | /* Initialize Caif devices list */ |
562 | static int __init caif_device_init(void) |
563 | { |
564 | int result; |
565 | |
566 | result = register_pernet_subsys(&caif_net_ops); |
567 | |
568 | if (result) |
569 | return result; |
570 | |
571 | register_netdevice_notifier(nb: &caif_device_notifier); |
572 | dev_add_pack(pt: &caif_packet_type); |
573 | |
574 | return result; |
575 | } |
576 | |
577 | static void __exit caif_device_exit(void) |
578 | { |
579 | unregister_netdevice_notifier(nb: &caif_device_notifier); |
580 | dev_remove_pack(pt: &caif_packet_type); |
581 | unregister_pernet_subsys(&caif_net_ops); |
582 | } |
583 | |
584 | module_init(caif_device_init); |
585 | module_exit(caif_device_exit); |
586 | |