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ALSA: hda/realtek - Change front mic location for Lenovo M710q
[linux/fpc-iii.git] / net / can / gw.c
blob53859346dc9a92f76daf35e4daf68a15ef1c2c9b
1 /*
2 * gw.c - CAN frame Gateway/Router/Bridge with netlink interface
3 *
4 * Copyright (c) 2017 Volkswagen Group Electronic Research
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of Volkswagen nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * Alternatively, provided that this notice is retained in full, this
20 * software may be distributed under the terms of the GNU General
21 * Public License ("GPL") version 2, in which case the provisions of the
22 * GPL apply INSTEAD OF those given above.
23 *
24 * The provided data structures and external interfaces from this code
25 * are not restricted to be used by modules with a GPL compatible license.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
30 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
31 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
32 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
33 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
34 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
35 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
36 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
37 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
38 * DAMAGE.
39 *
40 */
41
42 #include <linux/module.h>
43 #include <linux/init.h>
44 #include <linux/types.h>
45 #include <linux/kernel.h>
46 #include <linux/list.h>
47 #include <linux/spinlock.h>
48 #include <linux/rcupdate.h>
49 #include <linux/rculist.h>
50 #include <linux/net.h>
51 #include <linux/netdevice.h>
52 #include <linux/if_arp.h>
53 #include <linux/skbuff.h>
54 #include <linux/can.h>
55 #include <linux/can/core.h>
56 #include <linux/can/skb.h>
57 #include <linux/can/gw.h>
58 #include <net/rtnetlink.h>
59 #include <net/net_namespace.h>
60 #include <net/sock.h>
61
62 #define CAN_GW_VERSION "20170425"
63 #define CAN_GW_NAME "can-gw"
64
65 MODULE_DESCRIPTION("PF_CAN netlink gateway");
66 MODULE_LICENSE("Dual BSD/GPL");
67 MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
68 MODULE_ALIAS(CAN_GW_NAME);
69
70 #define CGW_MIN_HOPS 1
71 #define CGW_MAX_HOPS 6
72 #define CGW_DEFAULT_HOPS 1
73
74 static unsigned int max_hops __read_mostly = CGW_DEFAULT_HOPS;
75 module_param(max_hops, uint, 0444);
76 MODULE_PARM_DESC(max_hops,
77 "maximum " CAN_GW_NAME " routing hops for CAN frames "
78 "(valid values: " __stringify(CGW_MIN_HOPS) "-"
79 __stringify(CGW_MAX_HOPS) " hops, "
80 "default: " __stringify(CGW_DEFAULT_HOPS) ")");
81
82 static struct notifier_block notifier;
83 static struct kmem_cache *cgw_cache __read_mostly;
84
85 /* structure that contains the (on-the-fly) CAN frame modifications */
86 struct cf_mod {
87 struct {
88 struct can_frame and;
89 struct can_frame or;
90 struct can_frame xor;
91 struct can_frame set;
92 } modframe;
93 struct {
94 u8 and;
95 u8 or;
96 u8 xor;
97 u8 set;
98 } modtype;
99 void (*modfunc[MAX_MODFUNCTIONS])(struct can_frame *cf,
100 struct cf_mod *mod);
101
102 /* CAN frame checksum calculation after CAN frame modifications */
103 struct {
104 struct cgw_csum_xor xor;
105 struct cgw_csum_crc8 crc8;
106 } csum;
107 struct {
108 void (*xor)(struct can_frame *cf, struct cgw_csum_xor *xor);
109 void (*crc8)(struct can_frame *cf, struct cgw_csum_crc8 *crc8);
110 } csumfunc;
111 u32 uid;
112 };
113
114
115 /*
116 * So far we just support CAN -> CAN routing and frame modifications.
117 *
118 * The internal can_can_gw structure contains data and attributes for
119 * a CAN -> CAN gateway job.
120 */
121 struct can_can_gw {
122 struct can_filter filter;
123 int src_idx;
124 int dst_idx;
125 };
126
127 /* list entry for CAN gateways jobs */
128 struct cgw_job {
129 struct hlist_node list;
130 struct rcu_head rcu;
131 u32 handled_frames;
132 u32 dropped_frames;
133 u32 deleted_frames;
134 struct cf_mod mod;
135 union {
136 /* CAN frame data source */
137 struct net_device *dev;
138 } src;
139 union {
140 /* CAN frame data destination */
141 struct net_device *dev;
142 } dst;
143 union {
144 struct can_can_gw ccgw;
145 /* tbc */
146 };
147 u8 gwtype;
148 u8 limit_hops;
149 u16 flags;
150 };
151
152 /* modification functions that are invoked in the hot path in can_can_gw_rcv */
153
154 #define MODFUNC(func, op) static void func(struct can_frame *cf, \
155 struct cf_mod *mod) { op ; }
156
157 MODFUNC(mod_and_id, cf->can_id &= mod->modframe.and.can_id)
158 MODFUNC(mod_and_dlc, cf->can_dlc &= mod->modframe.and.can_dlc)
159 MODFUNC(mod_and_data, *(u64 *)cf->data &= *(u64 *)mod->modframe.and.data)
160 MODFUNC(mod_or_id, cf->can_id |= mod->modframe.or.can_id)
161 MODFUNC(mod_or_dlc, cf->can_dlc |= mod->modframe.or.can_dlc)
162 MODFUNC(mod_or_data, *(u64 *)cf->data |= *(u64 *)mod->modframe.or.data)
163 MODFUNC(mod_xor_id, cf->can_id ^= mod->modframe.xor.can_id)
164 MODFUNC(mod_xor_dlc, cf->can_dlc ^= mod->modframe.xor.can_dlc)
165 MODFUNC(mod_xor_data, *(u64 *)cf->data ^= *(u64 *)mod->modframe.xor.data)
166 MODFUNC(mod_set_id, cf->can_id = mod->modframe.set.can_id)
167 MODFUNC(mod_set_dlc, cf->can_dlc = mod->modframe.set.can_dlc)
168 MODFUNC(mod_set_data, *(u64 *)cf->data = *(u64 *)mod->modframe.set.data)
169
170 static inline void canframecpy(struct can_frame *dst, struct can_frame *src)
171 {
172 /*
173 * Copy the struct members separately to ensure that no uninitialized
174 * data are copied in the 3 bytes hole of the struct. This is needed
175 * to make easy compares of the data in the struct cf_mod.
176 */
177
178 dst->can_id = src->can_id;
179 dst->can_dlc = src->can_dlc;
180 *(u64 *)dst->data = *(u64 *)src->data;
181 }
182
183 static int cgw_chk_csum_parms(s8 fr, s8 to, s8 re)
184 {
185 /*
186 * absolute dlc values 0 .. 7 => 0 .. 7, e.g. data [0]
187 * relative to received dlc -1 .. -8 :
188 * e.g. for received dlc = 8
189 * -1 => index = 7 (data[7])
190 * -3 => index = 5 (data[5])
191 * -8 => index = 0 (data[0])
192 */
193
194 if (fr > -9 && fr < 8 &&
195 to > -9 && to < 8 &&
196 re > -9 && re < 8)
197 return 0;
198 else
199 return -EINVAL;
200 }
201
202 static inline int calc_idx(int idx, int rx_dlc)
203 {
204 if (idx < 0)
205 return rx_dlc + idx;
206 else
207 return idx;
208 }
209
210 static void cgw_csum_xor_rel(struct can_frame *cf, struct cgw_csum_xor *xor)
211 {
212 int from = calc_idx(xor->from_idx, cf->can_dlc);
213 int to = calc_idx(xor->to_idx, cf->can_dlc);
214 int res = calc_idx(xor->result_idx, cf->can_dlc);
215 u8 val = xor->init_xor_val;
216 int i;
217
218 if (from < 0 || to < 0 || res < 0)
219 return;
220
221 if (from <= to) {
222 for (i = from; i <= to; i++)
223 val ^= cf->data[i];
224 } else {
225 for (i = from; i >= to; i--)
226 val ^= cf->data[i];
227 }
228
229 cf->data[res] = val;
230 }
231
232 static void cgw_csum_xor_pos(struct can_frame *cf, struct cgw_csum_xor *xor)
233 {
234 u8 val = xor->init_xor_val;
235 int i;
236
237 for (i = xor->from_idx; i <= xor->to_idx; i++)
238 val ^= cf->data[i];
239
240 cf->data[xor->result_idx] = val;
241 }
242
243 static void cgw_csum_xor_neg(struct can_frame *cf, struct cgw_csum_xor *xor)
244 {
245 u8 val = xor->init_xor_val;
246 int i;
247
248 for (i = xor->from_idx; i >= xor->to_idx; i--)
249 val ^= cf->data[i];
250
251 cf->data[xor->result_idx] = val;
252 }
253
254 static void cgw_csum_crc8_rel(struct can_frame *cf, struct cgw_csum_crc8 *crc8)
255 {
256 int from = calc_idx(crc8->from_idx, cf->can_dlc);
257 int to = calc_idx(crc8->to_idx, cf->can_dlc);
258 int res = calc_idx(crc8->result_idx, cf->can_dlc);
259 u8 crc = crc8->init_crc_val;
260 int i;
261
262 if (from < 0 || to < 0 || res < 0)
263 return;
264
265 if (from <= to) {
266 for (i = crc8->from_idx; i <= crc8->to_idx; i++)
267 crc = crc8->crctab[crc^cf->data[i]];
268 } else {
269 for (i = crc8->from_idx; i >= crc8->to_idx; i--)
270 crc = crc8->crctab[crc^cf->data[i]];
271 }
272
273 switch (crc8->profile) {
274
275 case CGW_CRC8PRF_1U8:
276 crc = crc8->crctab[crc^crc8->profile_data[0]];
277 break;
278
279 case CGW_CRC8PRF_16U8:
280 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]];
281 break;
282
283 case CGW_CRC8PRF_SFFID_XOR:
284 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^
285 (cf->can_id >> 8 & 0xFF)];
286 break;
287
288 }
289
290 cf->data[crc8->result_idx] = crc^crc8->final_xor_val;
291 }
292
293 static void cgw_csum_crc8_pos(struct can_frame *cf, struct cgw_csum_crc8 *crc8)
294 {
295 u8 crc = crc8->init_crc_val;
296 int i;
297
298 for (i = crc8->from_idx; i <= crc8->to_idx; i++)
299 crc = crc8->crctab[crc^cf->data[i]];
300
301 switch (crc8->profile) {
302
303 case CGW_CRC8PRF_1U8:
304 crc = crc8->crctab[crc^crc8->profile_data[0]];
305 break;
306
307 case CGW_CRC8PRF_16U8:
308 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]];
309 break;
310
311 case CGW_CRC8PRF_SFFID_XOR:
312 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^
313 (cf->can_id >> 8 & 0xFF)];
314 break;
315 }
316
317 cf->data[crc8->result_idx] = crc^crc8->final_xor_val;
318 }
319
320 static void cgw_csum_crc8_neg(struct can_frame *cf, struct cgw_csum_crc8 *crc8)
321 {
322 u8 crc = crc8->init_crc_val;
323 int i;
324
325 for (i = crc8->from_idx; i >= crc8->to_idx; i--)
326 crc = crc8->crctab[crc^cf->data[i]];
327
328 switch (crc8->profile) {
329
330 case CGW_CRC8PRF_1U8:
331 crc = crc8->crctab[crc^crc8->profile_data[0]];
332 break;
333
334 case CGW_CRC8PRF_16U8:
335 crc = crc8->crctab[crc^crc8->profile_data[cf->data[1] & 0xF]];
336 break;
337
338 case CGW_CRC8PRF_SFFID_XOR:
339 crc = crc8->crctab[crc^(cf->can_id & 0xFF)^
340 (cf->can_id >> 8 & 0xFF)];
341 break;
342 }
343
344 cf->data[crc8->result_idx] = crc^crc8->final_xor_val;
345 }
346
347 /* the receive & process & send function */
348 static void can_can_gw_rcv(struct sk_buff *skb, void *data)
349 {
350 struct cgw_job *gwj = (struct cgw_job *)data;
351 struct can_frame *cf;
352 struct sk_buff *nskb;
353 int modidx = 0;
354
355 /*
356 * Do not handle CAN frames routed more than 'max_hops' times.
357 * In general we should never catch this delimiter which is intended
358 * to cover a misconfiguration protection (e.g. circular CAN routes).
359 *
360 * The Controller Area Network controllers only accept CAN frames with
361 * correct CRCs - which are not visible in the controller registers.
362 * According to skbuff.h documentation the csum_start element for IP
363 * checksums is undefined/unused when ip_summed == CHECKSUM_UNNECESSARY.
364 * Only CAN skbs can be processed here which already have this property.
365 */
366
367 #define cgw_hops(skb) ((skb)->csum_start)
368
369 BUG_ON(skb->ip_summed != CHECKSUM_UNNECESSARY);
370
371 if (cgw_hops(skb) >= max_hops) {
372 /* indicate deleted frames due to misconfiguration */
373 gwj->deleted_frames++;
374 return;
375 }
376
377 if (!(gwj->dst.dev->flags & IFF_UP)) {
378 gwj->dropped_frames++;
379 return;
380 }
381
382 /* is sending the skb back to the incoming interface not allowed? */
383 if (!(gwj->flags & CGW_FLAGS_CAN_IIF_TX_OK) &&
384 can_skb_prv(skb)->ifindex == gwj->dst.dev->ifindex)
385 return;
386
387 /*
388 * clone the given skb, which has not been done in can_rcv()
389 *
390 * When there is at least one modification function activated,
391 * we need to copy the skb as we want to modify skb->data.
392 */
393 if (gwj->mod.modfunc[0])
394 nskb = skb_copy(skb, GFP_ATOMIC);
395 else
396 nskb = skb_clone(skb, GFP_ATOMIC);
397
398 if (!nskb) {
399 gwj->dropped_frames++;
400 return;
401 }
402
403 /* put the incremented hop counter in the cloned skb */
404 cgw_hops(nskb) = cgw_hops(skb) + 1;
405
406 /* first processing of this CAN frame -> adjust to private hop limit */
407 if (gwj->limit_hops && cgw_hops(nskb) == 1)
408 cgw_hops(nskb) = max_hops - gwj->limit_hops + 1;
409
410 nskb->dev = gwj->dst.dev;
411
412 /* pointer to modifiable CAN frame */
413 cf = (struct can_frame *)nskb->data;
414
415 /* perform preprocessed modification functions if there are any */
416 while (modidx < MAX_MODFUNCTIONS && gwj->mod.modfunc[modidx])
417 (*gwj->mod.modfunc[modidx++])(cf, &gwj->mod);
418
419 /* Has the CAN frame been modified? */
420 if (modidx) {
421 /* get available space for the processed CAN frame type */
422 int max_len = nskb->len - offsetof(struct can_frame, data);
423
424 /* dlc may have changed, make sure it fits to the CAN frame */
425 if (cf->can_dlc > max_len)
426 goto out_delete;
427
428 /* check for checksum updates in classic CAN length only */
429 if (gwj->mod.csumfunc.crc8) {
430 if (cf->can_dlc > 8)
431 goto out_delete;
432
433 (*gwj->mod.csumfunc.crc8)(cf, &gwj->mod.csum.crc8);
434 }
435
436 if (gwj->mod.csumfunc.xor) {
437 if (cf->can_dlc > 8)
438 goto out_delete;
439
440 (*gwj->mod.csumfunc.xor)(cf, &gwj->mod.csum.xor);
441 }
442 }
443
444 /* clear the skb timestamp if not configured the other way */
445 if (!(gwj->flags & CGW_FLAGS_CAN_SRC_TSTAMP))
446 nskb->tstamp = 0;
447
448 /* send to netdevice */
449 if (can_send(nskb, gwj->flags & CGW_FLAGS_CAN_ECHO))
450 gwj->dropped_frames++;
451 else
452 gwj->handled_frames++;
453
454 return;
455
456 out_delete:
457 /* delete frame due to misconfiguration */
458 gwj->deleted_frames++;
459 kfree_skb(nskb);
460 return;
461 }
462
463 static inline int cgw_register_filter(struct net *net, struct cgw_job *gwj)
464 {
465 return can_rx_register(net, gwj->src.dev, gwj->ccgw.filter.can_id,
466 gwj->ccgw.filter.can_mask, can_can_gw_rcv,
467 gwj, "gw", NULL);
468 }
469
470 static inline void cgw_unregister_filter(struct net *net, struct cgw_job *gwj)
471 {
472 can_rx_unregister(net, gwj->src.dev, gwj->ccgw.filter.can_id,
473 gwj->ccgw.filter.can_mask, can_can_gw_rcv, gwj);
474 }
475
476 static int cgw_notifier(struct notifier_block *nb,
477 unsigned long msg, void *ptr)
478 {
479 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
480 struct net *net = dev_net(dev);
481
482 if (dev->type != ARPHRD_CAN)
483 return NOTIFY_DONE;
484
485 if (msg == NETDEV_UNREGISTER) {
486
487 struct cgw_job *gwj = NULL;
488 struct hlist_node *nx;
489
490 ASSERT_RTNL();
491
492 hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) {
493
494 if (gwj->src.dev == dev || gwj->dst.dev == dev) {
495 hlist_del(&gwj->list);
496 cgw_unregister_filter(net, gwj);
497 kmem_cache_free(cgw_cache, gwj);
498 }
499 }
500 }
501
502 return NOTIFY_DONE;
503 }
504
505 static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj, int type,
506 u32 pid, u32 seq, int flags)
507 {
508 struct cgw_frame_mod mb;
509 struct rtcanmsg *rtcan;
510 struct nlmsghdr *nlh;
511
512 nlh = nlmsg_put(skb, pid, seq, type, sizeof(*rtcan), flags);
513 if (!nlh)
514 return -EMSGSIZE;
515
516 rtcan = nlmsg_data(nlh);
517 rtcan->can_family = AF_CAN;
518 rtcan->gwtype = gwj->gwtype;
519 rtcan->flags = gwj->flags;
520
521 /* add statistics if available */
522
523 if (gwj->handled_frames) {
524 if (nla_put_u32(skb, CGW_HANDLED, gwj->handled_frames) < 0)
525 goto cancel;
526 }
527
528 if (gwj->dropped_frames) {
529 if (nla_put_u32(skb, CGW_DROPPED, gwj->dropped_frames) < 0)
530 goto cancel;
531 }
532
533 if (gwj->deleted_frames) {
534 if (nla_put_u32(skb, CGW_DELETED, gwj->deleted_frames) < 0)
535 goto cancel;
536 }
537
538 /* check non default settings of attributes */
539
540 if (gwj->limit_hops) {
541 if (nla_put_u8(skb, CGW_LIM_HOPS, gwj->limit_hops) < 0)
542 goto cancel;
543 }
544
545 if (gwj->mod.modtype.and) {
546 memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
547 mb.modtype = gwj->mod.modtype.and;
548 if (nla_put(skb, CGW_MOD_AND, sizeof(mb), &mb) < 0)
549 goto cancel;
550 }
551
552 if (gwj->mod.modtype.or) {
553 memcpy(&mb.cf, &gwj->mod.modframe.or, sizeof(mb.cf));
554 mb.modtype = gwj->mod.modtype.or;
555 if (nla_put(skb, CGW_MOD_OR, sizeof(mb), &mb) < 0)
556 goto cancel;
557 }
558
559 if (gwj->mod.modtype.xor) {
560 memcpy(&mb.cf, &gwj->mod.modframe.xor, sizeof(mb.cf));
561 mb.modtype = gwj->mod.modtype.xor;
562 if (nla_put(skb, CGW_MOD_XOR, sizeof(mb), &mb) < 0)
563 goto cancel;
564 }
565
566 if (gwj->mod.modtype.set) {
567 memcpy(&mb.cf, &gwj->mod.modframe.set, sizeof(mb.cf));
568 mb.modtype = gwj->mod.modtype.set;
569 if (nla_put(skb, CGW_MOD_SET, sizeof(mb), &mb) < 0)
570 goto cancel;
571 }
572
573 if (gwj->mod.uid) {
574 if (nla_put_u32(skb, CGW_MOD_UID, gwj->mod.uid) < 0)
575 goto cancel;
576 }
577
578 if (gwj->mod.csumfunc.crc8) {
579 if (nla_put(skb, CGW_CS_CRC8, CGW_CS_CRC8_LEN,
580 &gwj->mod.csum.crc8) < 0)
581 goto cancel;
582 }
583
584 if (gwj->mod.csumfunc.xor) {
585 if (nla_put(skb, CGW_CS_XOR, CGW_CS_XOR_LEN,
586 &gwj->mod.csum.xor) < 0)
587 goto cancel;
588 }
589
590 if (gwj->gwtype == CGW_TYPE_CAN_CAN) {
591
592 if (gwj->ccgw.filter.can_id || gwj->ccgw.filter.can_mask) {
593 if (nla_put(skb, CGW_FILTER, sizeof(struct can_filter),
594 &gwj->ccgw.filter) < 0)
595 goto cancel;
596 }
597
598 if (nla_put_u32(skb, CGW_SRC_IF, gwj->ccgw.src_idx) < 0)
599 goto cancel;
600
601 if (nla_put_u32(skb, CGW_DST_IF, gwj->ccgw.dst_idx) < 0)
602 goto cancel;
603 }
604
605 nlmsg_end(skb, nlh);
606 return 0;
607
608 cancel:
609 nlmsg_cancel(skb, nlh);
610 return -EMSGSIZE;
611 }
612
613 /* Dump information about all CAN gateway jobs, in response to RTM_GETROUTE */
614 static int cgw_dump_jobs(struct sk_buff *skb, struct netlink_callback *cb)
615 {
616 struct net *net = sock_net(skb->sk);
617 struct cgw_job *gwj = NULL;
618 int idx = 0;
619 int s_idx = cb->args[0];
620
621 rcu_read_lock();
622 hlist_for_each_entry_rcu(gwj, &net->can.cgw_list, list) {
623 if (idx < s_idx)
624 goto cont;
625
626 if (cgw_put_job(skb, gwj, RTM_NEWROUTE, NETLINK_CB(cb->skb).portid,
627 cb->nlh->nlmsg_seq, NLM_F_MULTI) < 0)
628 break;
629 cont:
630 idx++;
631 }
632 rcu_read_unlock();
633
634 cb->args[0] = idx;
635
636 return skb->len;
637 }
638
639 static const struct nla_policy cgw_policy[CGW_MAX+1] = {
640 [CGW_MOD_AND] = { .len = sizeof(struct cgw_frame_mod) },
641 [CGW_MOD_OR] = { .len = sizeof(struct cgw_frame_mod) },
642 [CGW_MOD_XOR] = { .len = sizeof(struct cgw_frame_mod) },
643 [CGW_MOD_SET] = { .len = sizeof(struct cgw_frame_mod) },
644 [CGW_CS_XOR] = { .len = sizeof(struct cgw_csum_xor) },
645 [CGW_CS_CRC8] = { .len = sizeof(struct cgw_csum_crc8) },
646 [CGW_SRC_IF] = { .type = NLA_U32 },
647 [CGW_DST_IF] = { .type = NLA_U32 },
648 [CGW_FILTER] = { .len = sizeof(struct can_filter) },
649 [CGW_LIM_HOPS] = { .type = NLA_U8 },
650 [CGW_MOD_UID] = { .type = NLA_U32 },
651 };
652
653 /* check for common and gwtype specific attributes */
654 static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
655 u8 gwtype, void *gwtypeattr, u8 *limhops)
656 {
657 struct nlattr *tb[CGW_MAX+1];
658 struct cgw_frame_mod mb;
659 int modidx = 0;
660 int err = 0;
661
662 /* initialize modification & checksum data space */
663 memset(mod, 0, sizeof(*mod));
664
665 err = nlmsg_parse(nlh, sizeof(struct rtcanmsg), tb, CGW_MAX,
666 cgw_policy, NULL);
667 if (err < 0)
668 return err;
669
670 if (tb[CGW_LIM_HOPS]) {
671 *limhops = nla_get_u8(tb[CGW_LIM_HOPS]);
672
673 if (*limhops < 1 || *limhops > max_hops)
674 return -EINVAL;
675 }
676
677 /* check for AND/OR/XOR/SET modifications */
678
679 if (tb[CGW_MOD_AND]) {
680 nla_memcpy(&mb, tb[CGW_MOD_AND], CGW_MODATTR_LEN);
681
682 canframecpy(&mod->modframe.and, &mb.cf);
683 mod->modtype.and = mb.modtype;
684
685 if (mb.modtype & CGW_MOD_ID)
686 mod->modfunc[modidx++] = mod_and_id;
687
688 if (mb.modtype & CGW_MOD_DLC)
689 mod->modfunc[modidx++] = mod_and_dlc;
690
691 if (mb.modtype & CGW_MOD_DATA)
692 mod->modfunc[modidx++] = mod_and_data;
693 }
694
695 if (tb[CGW_MOD_OR]) {
696 nla_memcpy(&mb, tb[CGW_MOD_OR], CGW_MODATTR_LEN);
697
698 canframecpy(&mod->modframe.or, &mb.cf);
699 mod->modtype.or = mb.modtype;
700
701 if (mb.modtype & CGW_MOD_ID)
702 mod->modfunc[modidx++] = mod_or_id;
703
704 if (mb.modtype & CGW_MOD_DLC)
705 mod->modfunc[modidx++] = mod_or_dlc;
706
707 if (mb.modtype & CGW_MOD_DATA)
708 mod->modfunc[modidx++] = mod_or_data;
709 }
710
711 if (tb[CGW_MOD_XOR]) {
712 nla_memcpy(&mb, tb[CGW_MOD_XOR], CGW_MODATTR_LEN);
713
714 canframecpy(&mod->modframe.xor, &mb.cf);
715 mod->modtype.xor = mb.modtype;
716
717 if (mb.modtype & CGW_MOD_ID)
718 mod->modfunc[modidx++] = mod_xor_id;
719
720 if (mb.modtype & CGW_MOD_DLC)
721 mod->modfunc[modidx++] = mod_xor_dlc;
722
723 if (mb.modtype & CGW_MOD_DATA)
724 mod->modfunc[modidx++] = mod_xor_data;
725 }
726
727 if (tb[CGW_MOD_SET]) {
728 nla_memcpy(&mb, tb[CGW_MOD_SET], CGW_MODATTR_LEN);
729
730 canframecpy(&mod->modframe.set, &mb.cf);
731 mod->modtype.set = mb.modtype;
732
733 if (mb.modtype & CGW_MOD_ID)
734 mod->modfunc[modidx++] = mod_set_id;
735
736 if (mb.modtype & CGW_MOD_DLC)
737 mod->modfunc[modidx++] = mod_set_dlc;
738
739 if (mb.modtype & CGW_MOD_DATA)
740 mod->modfunc[modidx++] = mod_set_data;
741 }
742
743 /* check for checksum operations after CAN frame modifications */
744 if (modidx) {
745
746 if (tb[CGW_CS_CRC8]) {
747 struct cgw_csum_crc8 *c = nla_data(tb[CGW_CS_CRC8]);
748
749 err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
750 c->result_idx);
751 if (err)
752 return err;
753
754 nla_memcpy(&mod->csum.crc8, tb[CGW_CS_CRC8],
755 CGW_CS_CRC8_LEN);
756
757 /*
758 * select dedicated processing function to reduce
759 * runtime operations in receive hot path.
760 */
761 if (c->from_idx < 0 || c->to_idx < 0 ||
762 c->result_idx < 0)
763 mod->csumfunc.crc8 = cgw_csum_crc8_rel;
764 else if (c->from_idx <= c->to_idx)
765 mod->csumfunc.crc8 = cgw_csum_crc8_pos;
766 else
767 mod->csumfunc.crc8 = cgw_csum_crc8_neg;
768 }
769
770 if (tb[CGW_CS_XOR]) {
771 struct cgw_csum_xor *c = nla_data(tb[CGW_CS_XOR]);
772
773 err = cgw_chk_csum_parms(c->from_idx, c->to_idx,
774 c->result_idx);
775 if (err)
776 return err;
777
778 nla_memcpy(&mod->csum.xor, tb[CGW_CS_XOR],
779 CGW_CS_XOR_LEN);
780
781 /*
782 * select dedicated processing function to reduce
783 * runtime operations in receive hot path.
784 */
785 if (c->from_idx < 0 || c->to_idx < 0 ||
786 c->result_idx < 0)
787 mod->csumfunc.xor = cgw_csum_xor_rel;
788 else if (c->from_idx <= c->to_idx)
789 mod->csumfunc.xor = cgw_csum_xor_pos;
790 else
791 mod->csumfunc.xor = cgw_csum_xor_neg;
792 }
793
794 if (tb[CGW_MOD_UID]) {
795 nla_memcpy(&mod->uid, tb[CGW_MOD_UID], sizeof(u32));
796 }
797 }
798
799 if (gwtype == CGW_TYPE_CAN_CAN) {
800
801 /* check CGW_TYPE_CAN_CAN specific attributes */
802
803 struct can_can_gw *ccgw = (struct can_can_gw *)gwtypeattr;
804 memset(ccgw, 0, sizeof(*ccgw));
805
806 /* check for can_filter in attributes */
807 if (tb[CGW_FILTER])
808 nla_memcpy(&ccgw->filter, tb[CGW_FILTER],
809 sizeof(struct can_filter));
810
811 err = -ENODEV;
812
813 /* specifying two interfaces is mandatory */
814 if (!tb[CGW_SRC_IF] || !tb[CGW_DST_IF])
815 return err;
816
817 ccgw->src_idx = nla_get_u32(tb[CGW_SRC_IF]);
818 ccgw->dst_idx = nla_get_u32(tb[CGW_DST_IF]);
819
820 /* both indices set to 0 for flushing all routing entries */
821 if (!ccgw->src_idx && !ccgw->dst_idx)
822 return 0;
823
824 /* only one index set to 0 is an error */
825 if (!ccgw->src_idx || !ccgw->dst_idx)
826 return err;
827 }
828
829 /* add the checks for other gwtypes here */
830
831 return 0;
832 }
833
834 static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh,
835 struct netlink_ext_ack *extack)
836 {
837 struct net *net = sock_net(skb->sk);
838 struct rtcanmsg *r;
839 struct cgw_job *gwj;
840 struct cf_mod mod;
841 struct can_can_gw ccgw;
842 u8 limhops = 0;
843 int err = 0;
844
845 if (!netlink_capable(skb, CAP_NET_ADMIN))
846 return -EPERM;
847
848 if (nlmsg_len(nlh) < sizeof(*r))
849 return -EINVAL;
850
851 r = nlmsg_data(nlh);
852 if (r->can_family != AF_CAN)
853 return -EPFNOSUPPORT;
854
855 /* so far we only support CAN -> CAN routings */
856 if (r->gwtype != CGW_TYPE_CAN_CAN)
857 return -EINVAL;
858
859 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops);
860 if (err < 0)
861 return err;
862
863 if (mod.uid) {
864
865 ASSERT_RTNL();
866
867 /* check for updating an existing job with identical uid */
868 hlist_for_each_entry(gwj, &net->can.cgw_list, list) {
869
870 if (gwj->mod.uid != mod.uid)
871 continue;
872
873 /* interfaces & filters must be identical */
874 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw)))
875 return -EINVAL;
876
877 /* update modifications with disabled softirq & quit */
878 local_bh_disable();
879 memcpy(&gwj->mod, &mod, sizeof(mod));
880 local_bh_enable();
881 return 0;
882 }
883 }
884
885 /* ifindex == 0 is not allowed for job creation */
886 if (!ccgw.src_idx || !ccgw.dst_idx)
887 return -ENODEV;
888
889 gwj = kmem_cache_alloc(cgw_cache, GFP_KERNEL);
890 if (!gwj)
891 return -ENOMEM;
892
893 gwj->handled_frames = 0;
894 gwj->dropped_frames = 0;
895 gwj->deleted_frames = 0;
896 gwj->flags = r->flags;
897 gwj->gwtype = r->gwtype;
898 gwj->limit_hops = limhops;
899
900 /* insert already parsed information */
901 memcpy(&gwj->mod, &mod, sizeof(mod));
902 memcpy(&gwj->ccgw, &ccgw, sizeof(ccgw));
903
904 err = -ENODEV;
905
906 gwj->src.dev = __dev_get_by_index(net, gwj->ccgw.src_idx);
907
908 if (!gwj->src.dev)
909 goto out;
910
911 if (gwj->src.dev->type != ARPHRD_CAN)
912 goto out;
913
914 gwj->dst.dev = __dev_get_by_index(net, gwj->ccgw.dst_idx);
915
916 if (!gwj->dst.dev)
917 goto out;
918
919 if (gwj->dst.dev->type != ARPHRD_CAN)
920 goto out;
921
922 ASSERT_RTNL();
923
924 err = cgw_register_filter(net, gwj);
925 if (!err)
926 hlist_add_head_rcu(&gwj->list, &net->can.cgw_list);
927 out:
928 if (err)
929 kmem_cache_free(cgw_cache, gwj);
930
931 return err;
932 }
933
934 static void cgw_remove_all_jobs(struct net *net)
935 {
936 struct cgw_job *gwj = NULL;
937 struct hlist_node *nx;
938
939 ASSERT_RTNL();
940
941 hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) {
942 hlist_del(&gwj->list);
943 cgw_unregister_filter(net, gwj);
944 kmem_cache_free(cgw_cache, gwj);
945 }
946 }
947
948 static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh,
949 struct netlink_ext_ack *extack)
950 {
951 struct net *net = sock_net(skb->sk);
952 struct cgw_job *gwj = NULL;
953 struct hlist_node *nx;
954 struct rtcanmsg *r;
955 struct cf_mod mod;
956 struct can_can_gw ccgw;
957 u8 limhops = 0;
958 int err = 0;
959
960 if (!netlink_capable(skb, CAP_NET_ADMIN))
961 return -EPERM;
962
963 if (nlmsg_len(nlh) < sizeof(*r))
964 return -EINVAL;
965
966 r = nlmsg_data(nlh);
967 if (r->can_family != AF_CAN)
968 return -EPFNOSUPPORT;
969
970 /* so far we only support CAN -> CAN routings */
971 if (r->gwtype != CGW_TYPE_CAN_CAN)
972 return -EINVAL;
973
974 err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops);
975 if (err < 0)
976 return err;
977
978 /* two interface indices both set to 0 => remove all entries */
979 if (!ccgw.src_idx && !ccgw.dst_idx) {
980 cgw_remove_all_jobs(net);
981 return 0;
982 }
983
984 err = -EINVAL;
985
986 ASSERT_RTNL();
987
988 /* remove only the first matching entry */
989 hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) {
990
991 if (gwj->flags != r->flags)
992 continue;
993
994 if (gwj->limit_hops != limhops)
995 continue;
996
997 /* we have a match when uid is enabled and identical */
998 if (gwj->mod.uid || mod.uid) {
999 if (gwj->mod.uid != mod.uid)
1000 continue;
1001 } else {
1002 /* no uid => check for identical modifications */
1003 if (memcmp(&gwj->mod, &mod, sizeof(mod)))
1004 continue;
1005 }
1006
1007 /* if (r->gwtype == CGW_TYPE_CAN_CAN) - is made sure here */
1008 if (memcmp(&gwj->ccgw, &ccgw, sizeof(ccgw)))
1009 continue;
1010
1011 hlist_del(&gwj->list);
1012 cgw_unregister_filter(net, gwj);
1013 kmem_cache_free(cgw_cache, gwj);
1014 err = 0;
1015 break;
1016 }
1017
1018 return err;
1019 }
1020
1021 static int __net_init cangw_pernet_init(struct net *net)
1022 {
1023 INIT_HLIST_HEAD(&net->can.cgw_list);
1024 return 0;
1025 }
1026
1027 static void __net_exit cangw_pernet_exit(struct net *net)
1028 {
1029 rtnl_lock();
1030 cgw_remove_all_jobs(net);
1031 rtnl_unlock();
1032 }
1033
1034 static struct pernet_operations cangw_pernet_ops = {
1035 .init = cangw_pernet_init,
1036 .exit = cangw_pernet_exit,
1037 };
1038
1039 static __init int cgw_module_init(void)
1040 {
1041 int ret;
1042
1043 /* sanitize given module parameter */
1044 max_hops = clamp_t(unsigned int, max_hops, CGW_MIN_HOPS, CGW_MAX_HOPS);
1045
1046 pr_info("can: netlink gateway (rev " CAN_GW_VERSION ") max_hops=%d\n",
1047 max_hops);
1048
1049 register_pernet_subsys(&cangw_pernet_ops);
1050 cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job),
1051 0, 0, NULL);
1052
1053 if (!cgw_cache)
1054 return -ENOMEM;
1055
1056 /* set notifier */
1057 notifier.notifier_call = cgw_notifier;
1058 register_netdevice_notifier(&notifier);
1059
1060 ret = rtnl_register_module(THIS_MODULE, PF_CAN, RTM_GETROUTE,
1061 NULL, cgw_dump_jobs, 0);
1062 if (ret) {
1063 unregister_netdevice_notifier(&notifier);
1064 kmem_cache_destroy(cgw_cache);
1065 return -ENOBUFS;
1066 }
1067
1068 /* Only the first call to rtnl_register_module can fail */
1069 rtnl_register_module(THIS_MODULE, PF_CAN, RTM_NEWROUTE,
1070 cgw_create_job, NULL, 0);
1071 rtnl_register_module(THIS_MODULE, PF_CAN, RTM_DELROUTE,
1072 cgw_remove_job, NULL, 0);
1073
1074 return 0;
1075 }
1076
1077 static __exit void cgw_module_exit(void)
1078 {
1079 rtnl_unregister_all(PF_CAN);
1080
1081 unregister_netdevice_notifier(&notifier);
1082
1083 unregister_pernet_subsys(&cangw_pernet_ops);
1084 rcu_barrier(); /* Wait for completion of call_rcu()'s */
1085
1086 kmem_cache_destroy(cgw_cache);
1087 }
1088
1089 module_init(cgw_module_init);
1090 module_exit(cgw_module_exit);
Linux with added FPC-III support